diff --git a/frontend/apps/reader/readerui.lua b/frontend/apps/reader/readerui.lua
index 352da8887..dc5c3be0c 100644
--- a/frontend/apps/reader/readerui.lua
+++ b/frontend/apps/reader/readerui.lua
@@ -1,10 +1,11 @@
 local InputContainer = require("ui/widget/container/inputcontainer")
-local Cache = require("cache")
+local ConfirmBox = require("ui/widget/confirmbox")
+local DocSettings = require("docsettings")
+local UIManager = require("ui/uimanager")
 local Geom = require("ui/geometry")
 local Device = require("ui/device")
-local DocSettings = require("docsettings")
 local Event = require("ui/event")
-local UIManager = require("ui/uimanager")
+local Cache = require("cache")
 local DEBUG = require("dbg")
 local _ = require("gettext")
 
@@ -56,8 +57,6 @@ local ReaderUI = InputContainer:new{
     -- the document interface
     document = nil,
 
-    -- initial page or percent inside document on opening
-    start_pos = nil,
     -- password for document unlock
     password = nil,
 
@@ -307,14 +306,36 @@ function ReaderUI:onFlushSettings()
     return true
 end
 
+function ReaderUI:closeDocument()
+    self.document:close()
+    self.document = nil
+end
+
+function ReaderUI:onCloseDocument()
+    if self.document:isEdited() then
+        UIManager:show(ConfirmBox:new{
+            text = _("Do you want to save this document?"),
+            ok_text = _("Yes"),
+            cancel_text = _("No"),
+            ok_callback = function()
+                self:closeDocument()
+            end,
+            cancel_callback = function()
+                self.document:discardChange()
+                self:closeDocument()
+            end,
+        })
+    else
+        self:closeDocument()
+    end
+end
+
 function ReaderUI:onClose()
     DEBUG("closing reader")
     self:saveSettings()
-    self:handleEvent(Event:new("CloseReader"))
     if self.document ~= nil then
-        self.document:close()
-        self.document = nil
-        self.start_pos = nil
+        DEBUG("closing document")
+        self:onCloseDocument()
     end
     UIManager:close(self.dialog)
     -- serialize last used items for later launch
diff --git a/frontend/document/document.lua b/frontend/document/document.lua
index 5dbdb6109..6fa8b86fe 100644
--- a/frontend/document/document.lua
+++ b/frontend/document/document.lua
@@ -51,6 +51,9 @@ local Document = {
 
     -- flag to show that the document needs to be unlocked by a password
     is_locked = false,
+
+    -- flag to show that the document is edited and needs to write back to disk
+    is_edited = false,
 }
 
 function Document:new(o)
@@ -85,6 +88,17 @@ function Document:close()
     end
 end
 
+-- check if document is edited and needs to write to disk
+function Document:isEdited()
+    return self.is_edited
+end
+
+-- discard change will set is_edited flag to false and implematation of Document
+-- should check the is_edited flag before writing document
+function Document:discardChange()
+    self.is_edited = false
+end
+
 -- this might be overridden by a document implementation
 function Document:getNativePageDimensions(pageno)
     local hash = "pgdim|"..self.file.."|"..pageno
diff --git a/frontend/document/pdfdocument.lua b/frontend/document/pdfdocument.lua
index 5e85a8353..ea88d92d7 100644
--- a/frontend/document/pdfdocument.lua
+++ b/frontend/document/pdfdocument.lua
@@ -4,6 +4,7 @@ local KoptOptions = require("ui/data/koptoptions")
 local Document = require("document/document")
 local Configurable = require("configurable")
 local DrawContext = require("ffi/drawcontext")
+local DEBUG = require("dbg")
 local ffi = require("ffi")
 ffi.cdef[[
 typedef struct fz_point_s fz_point;
@@ -46,7 +47,6 @@ local PdfDocument = Document:new{
     dc_null = DrawContext.new(),
     options = KoptOptions,
     koptinterface = nil,
-    annot_revision = 0,
 }
 
 function PdfDocument:init()
@@ -152,7 +152,7 @@ function PdfDocument:getPageLinks(pageno)
 end
 
 function PdfDocument:saveHighlight(pageno, item)
-    self.annot_revision = self.annot_revision + 1
+    self.is_edited = true
     local n = #item.pboxes
     local quadpoints = ffi.new("fz_point[?]", 4*n)
     for i=1, n do
@@ -179,11 +179,12 @@ function PdfDocument:saveHighlight(pageno, item)
 end
 
 function PdfDocument:writeDocument()
+    DEBUG("writing document to", self.file)
     self._document:writeDocument(self.file)
 end
 
 function PdfDocument:close()
-    if self.annot_revision ~= 0 then
+    if self.is_edited then
         self:writeDocument()
     end
     Document.close(self)