diff --git a/bar.go b/bar.go
index a1c3a38..3d31501 100644
--- a/bar.go
+++ b/bar.go
@@ -141,7 +141,11 @@
 	if !ok {
 		rc = ioutil.NopCloser(r)
 	}
-	return &proxyReader{rc, b, time.Now()}
+	prox := &proxyReader{rc, b, time.Now()}
+	if wt, ok := r.(io.WriterTo); ok {
+		return &proxyWriterTo{prox, wt}
+	}
+	return prox
 }
 
 // ID returs id of the bar.
diff --git a/proxyreader.go b/proxyreader.go
index 425e57a..1034fe6 100644
--- a/proxyreader.go
+++ b/proxyreader.go
@@ -5,24 +5,41 @@
 	"time"
 )
 
-// proxyReader is io.Reader wrapper, for proxy read bytes
 type proxyReader struct {
 	io.ReadCloser
 	bar *Bar
 	iT  time.Time
 }
 
-func (pr *proxyReader) Read(p []byte) (n int, err error) {
-	n, err = pr.ReadCloser.Read(p)
+func (prox *proxyReader) Read(p []byte) (n int, err error) {
+	n, err = prox.ReadCloser.Read(p)
 	if n > 0 {
-		pr.bar.IncrBy(n, time.Since(pr.iT))
-		pr.iT = time.Now()
+		prox.bar.IncrBy(n, time.Since(prox.iT))
+		prox.iT = time.Now()
 	}
 	if err == io.EOF {
 		go func() {
-			current := pr.bar.Current()
-			pr.bar.SetTotal(current, true)
+			prox.bar.SetTotal(prox.bar.Current(), true)
 		}()
 	}
 	return
 }
+
+type proxyWriterTo struct {
+	*proxyReader
+	wt io.WriterTo
+}
+
+func (prox *proxyWriterTo) WriteTo(w io.Writer) (n int64, err error) {
+	n, err = prox.wt.WriteTo(w)
+	if n > 0 {
+		prox.bar.IncrInt64(n, time.Since(prox.iT))
+		prox.iT = time.Now()
+	}
+	if err == io.EOF {
+		go func() {
+			prox.bar.SetTotal(prox.bar.Current(), true)
+		}()
+	}
+	return
+}
diff --git a/proxyreader_test.go b/proxyreader_test.go
index 280e54a..2042e9e 100644
--- a/proxyreader_test.go
+++ b/proxyreader_test.go
@@ -1,6 +1,7 @@
 package mpb_test
 
 import (
+	"bytes"
 	"io"
 	"io/ioutil"
 	"strings"
@@ -28,26 +29,62 @@
 }
 
 func TestProxyReader(t *testing.T) {
-
 	p := mpb.New(mpb.WithOutput(ioutil.Discard))
 
-	reader := &testReader{Reader: strings.NewReader(content)}
+	tReader := &testReader{strings.NewReader(content), false}
 
-	total := len(content)
-	bar := p.AddBar(100, mpb.TrimSpace())
+	bar := p.AddBar(int64(len(content)), mpb.TrimSpace())
 
-	written, err := io.Copy(ioutil.Discard, bar.ProxyReader(reader))
+	var buf bytes.Buffer
+	_, err := io.Copy(&buf, bar.ProxyReader(tReader))
 	if err != nil {
 		t.Errorf("Error copying from reader: %+v\n", err)
 	}
 
 	p.Wait()
 
-	if !reader.called {
+	if !tReader.called {
 		t.Error("Read not called")
 	}
 
-	if written != int64(total) {
-		t.Errorf("Expected written: %d, got: %d\n", total, written)
+	if got := buf.String(); got != content {
+		t.Errorf("Expected content: %s, got: %s\n", content, got)
 	}
 }
+
+type testWriterTo struct {
+	io.Reader
+	wt     io.WriterTo
+	called bool
+}
+
+func (wt *testWriterTo) WriteTo(w io.Writer) (n int64, err error) {
+	wt.called = true
+	return wt.wt.WriteTo(w)
+}
+
+func TestProxyWriterTo(t *testing.T) {
+	p := mpb.New(mpb.WithOutput(ioutil.Discard))
+
+	var reader io.Reader = strings.NewReader(content)
+	wt := reader.(io.WriterTo)
+	tReader := &testWriterTo{reader, wt, false}
+
+	bar := p.AddBar(int64(len(content)), mpb.TrimSpace())
+
+	var buf bytes.Buffer
+	_, err := io.Copy(&buf, bar.ProxyReader(tReader))
+	if err != nil {
+		t.Errorf("Error copying from reader: %+v\n", err)
+	}
+
+	p.Wait()
+
+	if !tReader.called {
+		t.Error("WriteTo not called")
+	}
+
+	if got := buf.String(); got != content {
+		t.Errorf("Expected content: %s, got: %s\n", content, got)
+	}
+}