diff --git a/tail.go b/tail.go
index 753158d..5532ac1 100644
--- a/tail.go
+++ b/tail.go
@@ -290,11 +290,11 @@ func (tail *Tail) tailFileSync() {
 // reopened if ReOpen is true. Truncated files are always reopened.
 func (tail *Tail) waitForChanges() error {
 	if tail.changes == nil {
-		st, err := tail.file.Stat()
+		pos, err := tail.file.Seek(0, os.SEEK_CUR)
 		if err != nil {
 			return err
 		}
-		tail.changes = tail.watcher.ChangeEvents(&tail.Tomb, st)
+		tail.changes = tail.watcher.ChangeEvents(&tail.Tomb, pos)
 	}
 
 	select {
@@ -340,7 +340,7 @@ func (tail *Tail) openReader() {
 }
 
 func (tail *Tail) seekEnd() error {
-	return tail.seekTo(SeekInfo{Offset: 0, Whence: 2})
+	return tail.seekTo(SeekInfo{Offset: 0, Whence: os.SEEK_END})
 }
 
 func (tail *Tail) seekTo(pos SeekInfo) error {
diff --git a/watch/inotify.go b/watch/inotify.go
index 258e3ef..d6635f4 100644
--- a/watch/inotify.go
+++ b/watch/inotify.go
@@ -58,7 +58,7 @@ func (fw *InotifyFileWatcher) BlockUntilExists(t *tomb.Tomb) error {
 	panic("unreachable")
 }
 
-func (fw *InotifyFileWatcher) ChangeEvents(t *tomb.Tomb, fi os.FileInfo) *FileChanges {
+func (fw *InotifyFileWatcher) ChangeEvents(t *tomb.Tomb, pos int64) *FileChanges {
 	changes := NewFileChanges()
 
 	err := Watch(fw.Filename)
@@ -66,7 +66,7 @@ func (fw *InotifyFileWatcher) ChangeEvents(t *tomb.Tomb, fi os.FileInfo) *FileCh
 		go changes.NotifyDeleted()
 	}
 
-	fw.Size = fi.Size()
+	fw.Size = pos
 
 	go func() {
 		defer RemoveWatch(fw.Filename)
diff --git a/watch/polling.go b/watch/polling.go
index e13e034..5479272 100644
--- a/watch/polling.go
+++ b/watch/polling.go
@@ -40,14 +40,19 @@ func (fw *PollingFileWatcher) BlockUntilExists(t *tomb.Tomb) error {
 	panic("unreachable")
 }
 
-func (fw *PollingFileWatcher) ChangeEvents(t *tomb.Tomb, origFi os.FileInfo) *FileChanges {
+func (fw *PollingFileWatcher) ChangeEvents(t *tomb.Tomb, pos int64) *FileChanges {
 	changes := NewFileChanges()
 	var prevModTime time.Time
 
 	// XXX: use tomb.Tomb to cleanly manage these goroutines. replace
 	// the fatal (below) with tomb's Kill.
 
-	fw.Size = origFi.Size()
+	fw.Size = pos
+	origFi, err := os.Stat(fw.Filename)
+	if err != nil {
+		changes.NotifyDeleted()
+		return changes
+	}
 
 	go func() {
 		defer changes.Close()
diff --git a/watch/watch.go b/watch/watch.go
index a3c06e8..fbc08a5 100644
--- a/watch/watch.go
+++ b/watch/watch.go
@@ -2,10 +2,7 @@
 
 package watch
 
-import (
-	"gopkg.in/tomb.v1"
-	"os"
-)
+import "gopkg.in/tomb.v1"
 
 // FileWatcher monitors file-level events.
 type FileWatcher interface {
@@ -16,5 +13,7 @@ type FileWatcher interface {
 	// deletion, renames or truncations. Returned FileChanges group of
 	// channels will be closed, thus become unusable, after a deletion
 	// or truncation event.
-	ChangeEvents(*tomb.Tomb, os.FileInfo) *FileChanges
+	// In order to properly report truncations, ChangeEvents requires
+	// the caller to pass their current offset in the file.
+	ChangeEvents(*tomb.Tomb, int64) *FileChanges
 }