diff --git a/app/src/main/java/it/danieleverducci/lunatracker/MainActivity.kt b/app/src/main/java/it/danieleverducci/lunatracker/MainActivity.kt
index 252bb60..b593bbb 100644
--- a/app/src/main/java/it/danieleverducci/lunatracker/MainActivity.kt
+++ b/app/src/main/java/it/danieleverducci/lunatracker/MainActivity.kt
@@ -330,7 +330,7 @@ class MainActivity : AppCompatActivity() {
         alertDialog.show()
     }
 
-    fun datePickerHelper(time: Long, dateTextView: TextView): Calendar {
+    fun datePickerHelper(time: Long, dateTextView: TextView, onChange: () -> Unit = {}): Calendar {
         dateTextView.text = DateUtils.formatDateTime(time)
 
         val dateTime = Calendar.getInstance()
@@ -349,6 +349,7 @@ class MainActivity : AppCompatActivity() {
                     { _, hour, minute ->
                         dateTime.set(year, month, day, hour, minute)
                         dateTextView.text = DateUtils.formatDateTime(dateTime.time.time / 1000)
+                        onChange.invoke()
                     },
                     startHour,
                     startMinute,
@@ -371,6 +372,74 @@ class MainActivity : AppCompatActivity() {
         saveLogbook()
     }
 
+    fun addSleepEvent(event: LunaEvent) {
+        askSleepValue(event) { saveEvent(event) }
+    }
+
+    fun askSleepValue(event: LunaEvent, onPositive: () -> Unit) {
+        val d = AlertDialog.Builder(this)
+        val dialogView = layoutInflater.inflate(R.layout.dialog_edit_duration, null)
+        d.setTitle(event.getTypeDescription(this))
+        d.setMessage(event.getDialogMessage(this))
+        d.setView(dialogView)
+
+        val fromTextView = dialogView.findViewById<TextView>(R.id.dialog_date_from)
+        val toTextView = dialogView.findViewById<TextView>(R.id.dialog_date_to)
+        val durationTextView = dialogView.findViewById<TextView>(R.id.dialog_date_duration)
+
+        var pickedFromTime = Calendar.getInstance()
+        var pickedToTime = Calendar.getInstance()
+
+        fun isValidTime(fromSeconds: Long, toSeconds: Long): Boolean {
+            if (fromSeconds < toSeconds) {
+                val durationSeconds = toSeconds - fromSeconds
+                // sleep between 0 seconds and 12 hours
+                return durationSeconds > 0 && durationSeconds < (12 * 60 * 60)
+            } else {
+                return false
+            }
+        }
+
+        val onDateChange = {
+            val fromSeconds = pickedFromTime.time.time / 1000
+            val toSeconds = pickedToTime.time.time / 1000
+
+            durationTextView.text = DateUtils.formatTimeDuration(applicationContext, toSeconds - fromSeconds)
+
+            if (isValidTime(fromSeconds, toSeconds)) {
+                // valid duration: set default color
+                durationTextView.setTextColor(durationTextView.textColors.defaultColor)
+            } else {
+                // invalid duration: set danger color
+                durationTextView.setTextColor(ContextCompat.getColor(this, R.color.danger))
+            }
+        }
+
+        pickedFromTime = datePickerHelper(event.time, fromTextView, onDateChange)
+        pickedToTime = datePickerHelper(event.time + event.quantity, toTextView, onDateChange)
+
+        d.setPositiveButton(android.R.string.ok) { dialogInterface, i ->
+            val fromSeconds = pickedFromTime.time.time / 1000
+            val toSeconds = pickedToTime.time.time / 1000
+
+            if (isValidTime(fromSeconds, toSeconds)) {
+                event.time = fromSeconds
+                event.quantity = (toSeconds - fromSeconds).toInt()
+                onPositive()
+            } else {
+                Toast.makeText(applicationContext, R.string.toast_date_error, Toast.LENGTH_SHORT).show()
+            }
+            dialogInterface.dismiss()
+        }
+
+        d.setNegativeButton(android.R.string.cancel) { dialogInterface, i ->
+            dialogInterface.dismiss()
+        }
+
+        val alertDialog = d.create()
+        alertDialog.show()
+    }
+
     fun addAmountEvent(event: LunaEvent) {
         askAmountValue(event, true) { saveEvent(event) }
     }
@@ -643,6 +712,7 @@ class MainActivity : AppCompatActivity() {
                 LunaEvent.TYPE_PUKE -> askAmountValue(event, false, updateValues)
                 LunaEvent.TYPE_TEMPERATURE -> askTemperatureValue(event, false, updateValues)
                 LunaEvent.TYPE_NOTE -> askNotes(event, false, updateValues)
+                LunaEvent.TYPE_SLEEP -> askSleepValue(event, updateValues)
             }
         }
 
@@ -1100,6 +1170,10 @@ class MainActivity : AppCompatActivity() {
                 addAmountEvent(LunaEvent(LunaEvent.TYPE_PUKE))
                 dismiss()
             }
+            contentView.findViewById<View>(R.id.button_sleep).setOnClickListener {
+                addSleepEvent(LunaEvent(LunaEvent.TYPE_SLEEP))
+                dismiss()
+            }
             contentView.findViewById<View>(R.id.button_colic).setOnClickListener {
                 addPlainEvent(LunaEvent(LunaEvent.TYPE_COLIC))
                 dismiss()
diff --git a/app/src/main/java/it/danieleverducci/lunatracker/entities/LunaEvent.kt b/app/src/main/java/it/danieleverducci/lunatracker/entities/LunaEvent.kt
index 1eade79..63e268b 100644
--- a/app/src/main/java/it/danieleverducci/lunatracker/entities/LunaEvent.kt
+++ b/app/src/main/java/it/danieleverducci/lunatracker/entities/LunaEvent.kt
@@ -30,6 +30,7 @@ class LunaEvent: Comparable<LunaEvent> {
         const val TYPE_FOOD = "FOOD"
         const val TYPE_PUKE = "PUKE"
         const val TYPE_BATH = "BATH"
+        const val TYPE_SLEEP = "SLEEP"
     }
 
     private val jo: JSONObject
@@ -111,6 +112,7 @@ class LunaEvent: Comparable<LunaEvent> {
                 TYPE_FOOD -> R.string.event_food_type
                 TYPE_PUKE -> R.string.event_puke_type
                 TYPE_BATH -> R.string.event_bath_type
+                TYPE_SLEEP -> R.string.event_sleep_type
                 else -> R.string.event_unknown_type
             }
         )
@@ -134,6 +136,7 @@ class LunaEvent: Comparable<LunaEvent> {
                 TYPE_FOOD -> R.string.event_food_desc
                 TYPE_PUKE -> R.string.event_puke_desc
                 TYPE_BATH -> R.string.event_bath_desc
+                TYPE_SLEEP -> R.string.event_sleep_desc
                 else -> R.string.event_unknown_desc
             }
         )
@@ -149,6 +152,7 @@ class LunaEvent: Comparable<LunaEvent> {
                 TYPE_DIAPERCHANGE_PEE,
                 TYPE_PUKE -> R.string.log_amount_dialog_description
                 TYPE_WEIGHT -> R.string.log_weight_dialog_description
+                TYPE_SLEEP -> R.string.log_sleep_dialog_description
                 else -> R.string.log_unknown_dialog_description
             }
         )
diff --git a/app/src/main/java/utils/NumericUtils.kt b/app/src/main/java/utils/NumericUtils.kt
index 8d12c35..6b2aa48 100644
--- a/app/src/main/java/utils/NumericUtils.kt
+++ b/app/src/main/java/utils/NumericUtils.kt
@@ -7,6 +7,7 @@ import android.os.Build
 import android.util.Log
 import it.danieleverducci.lunatracker.R
 import it.danieleverducci.lunatracker.entities.LunaEvent
+import utils.DateUtils.Companion.formatTimeDuration
 import java.text.NumberFormat
 
 class NumericUtils (val context: Context) {
@@ -76,6 +77,7 @@ class NumericUtils (val context: Context) {
                         return ""
                     }
                 }
+                LunaEvent.TYPE_SLEEP -> formatTimeDuration(context, event.quantity.toLong())
                 else ->
                     event.quantity
             })
diff --git a/app/src/main/res/layout/more_events_popup.xml b/app/src/main/res/layout/more_events_popup.xml
index b1dfbea..ef0cdf7 100644
--- a/app/src/main/res/layout/more_events_popup.xml
+++ b/app/src/main/res/layout/more_events_popup.xml
@@ -49,6 +49,16 @@
                 style="@style/OverflowMenuText"
                 android:text="@string/overflow_event_puke"/>
 
+            <TextView
+                android:id="@+id/button_sleep"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:layout_marginTop="10dp"
+                android:padding="10dp"
+                android:background="@drawable/dropdown_list_item_background"
+                style="@style/OverflowMenuText"
+                android:text="@string/overflow_event_sleep"/>
+
             <TextView
                 android:id="@+id/button_colic"
                 android:layout_width="match_parent"
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 487a06c..1743969 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -18,6 +18,7 @@
     <string name="event_colic_type" translatable="false">💨</string>
     <string name="event_puke_type" translatable="false">🤮</string>
     <string name="event_bath_type" translatable="false">🛁</string>
+    <string name="event_sleep_type" translatable="false">💤</string>
     <string name="event_unknown_type" translatable="false">\?</string>
 
     <string name="event_bottle_desc">Baby bottle</string>
@@ -35,6 +36,7 @@
     <string name="event_colic_desc">Gaseous colic</string>
     <string name="event_puke_desc">Puke</string>
     <string name="event_bath_desc">Bath</string>
+    <string name="event_sleep_desc">Sleep</string>
     <string name="event_unknown_desc"></string>
 
     <string name="overflow_event_weight">⚖️ Weight</string>
@@ -44,12 +46,14 @@
     <string name="overflow_event_temperature">🌡️ Temperature</string>
     <string name="overflow_event_colic">💨 Gaseous colic</string>
     <string name="overflow_event_puke">🤮 Puke</string>
+    <string name="overflow_event_sleep">💤 Sleep</string>
     <string name="overflow_event_bath">🛁 Bath</string>
 
     <string name="toast_event_added">Event logged</string>
     <string name="toast_logbook_saved">Logbook saved</string>
     <string name="toast_event_add_error">Unable to log the event</string>
     <string name="toast_integer_error">Invalid value. Insert an integer.</string>
+    <string name="toast_date_error">Invalid date.</string>
 
     <string name="now">now</string>
     <string name="second_ago">sec</string>
@@ -112,6 +116,7 @@
     <string name="log_temperature_dialog_description">Select the temperature:</string>
     <string name="log_unknown_dialog_description"></string>
     <string name="log_weight_dialog_description">Insert the weight:</string>
+    <string name="log_sleep_dialog_description">Select sleep range:</string>
 
     <string name="measurement_unit_liquid_base_metric" translatable="false">ml</string>
     <string name="measurement_unit_weight_base_metric" translatable="false">g</string>