diff --git a/mime.go b/mime.go
index bbc1c37..3859157 100644
--- a/mime.go
+++ b/mime.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"mime/multipart"
+	"mime/quotedprintable"
 	"net/textproto"
 )
 
@@ -142,12 +143,17 @@ func (m *MailYak) writeBody(w io.Writer, boundary string) error {
 		c := fmt.Sprintf("%s; charset=UTF-8", ctype)
 
 		var part io.Writer
-		part, err = alt.CreatePart(textproto.MIMEHeader{"Content-Type": {c}})
+		part, err = alt.CreatePart(textproto.MIMEHeader{"Content-Type": {c}, "Content-Transfer-Encoding": {"quoted-printable"}})
 		if err != nil {
 			return
 		}
 
-		_, err = part.Write(data)
+		var buf bytes.Buffer
+		qpw := quotedprintable.NewWriter(&buf)
+		_, err = qpw.Write(data)
+		qpw.Close()
+
+		_, err = part.Write(buf.Bytes())
 	}
 
 	writePart("text/plain", m.plain.Bytes())
diff --git a/mime_test.go b/mime_test.go
index 0b7b4dd..8a8d5d2 100644
--- a/mime_test.go
+++ b/mime_test.go
@@ -227,7 +227,7 @@ func TestMailYakWriteBody(t *testing.T) {
 			"HTML",
 			"",
 			"t",
-			"--t\r\nContent-Type: text/html; charset=UTF-8\r\n\r\nHTML\r\n--t--\r\n",
+			"--t\r\nContent-Transfer-Encoding: quoted-printable\r\nContent-Type: text/html; charset=UTF-8\r\n\r\nHTML\r\n--t--\r\n",
 			false,
 		},
 		{
@@ -235,7 +235,7 @@ func TestMailYakWriteBody(t *testing.T) {
 			"",
 			"Plain",
 			"t",
-			"--t\r\nContent-Type: text/plain; charset=UTF-8\r\n\r\nPlain\r\n--t--\r\n",
+			"--t\r\nContent-Transfer-Encoding: quoted-printable\r\nContent-Type: text/plain; charset=UTF-8\r\n\r\nPlain\r\n--t--\r\n",
 			false,
 		},
 		{
@@ -243,7 +243,15 @@ func TestMailYakWriteBody(t *testing.T) {
 			"HTML",
 			"Plain",
 			"t",
-			"--t\r\nContent-Type: text/plain; charset=UTF-8\r\n\r\nPlain\r\n--t\r\nContent-Type: text/html; charset=UTF-8\r\n\r\nHTML\r\n--t--\r\n",
+			"--t\r\nContent-Transfer-Encoding: quoted-printable\r\nContent-Type: text/plain; charset=UTF-8\r\n\r\nPlain\r\n--t\r\nContent-Transfer-Encoding: quoted-printable\r\nContent-Type: text/html; charset=UTF-8\r\n\r\nHTML\r\n--t--\r\n",
+			false,
+		},
+		{
+			"Both with long lines",
+			"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.",
+			"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.",
+			"t",
+			"--t\r\nContent-Transfer-Encoding: quoted-printable\r\nContent-Type: text/plain; charset=UTF-8\r\n\r\nLorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tem=\r\npor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, q=\r\nuis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo cons=\r\nequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillu=\r\nm dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non pr=\r\noident, sunt in culpa qui officia deserunt mollit anim id est laborum.\r\n--t\r\nContent-Transfer-Encoding: quoted-printable\r\nContent-Type: text/html; charset=UTF-8\r\n\r\nLorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tem=\r\npor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, q=\r\nuis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo cons=\r\nequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillu=\r\nm dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non pr=\r\noident, sunt in culpa qui officia deserunt mollit anim id est laborum.\r\n--t--\r\n",
 			false,
 		},
 	}
@@ -309,7 +317,7 @@ func TestMailYakBuildMime(t *testing.T) {
 			"",
 			"",
 			"",
-			"From: \r\nMime-Version: 1.0\r\nDate: " + now + "\r\nSubject: \r\nTo: \r\nContent-Type: multipart/mixed;\r\n\tboundary=\"mixed\"; charset=UTF-8\r\n\r\n--mixed\r\nContent-Type: multipart/alternative;\r\n\tboundary=\"alt\"\r\n\r\n--alt\r\nContent-Type: text/html; charset=UTF-8\r\n\r\nHTML\r\n--alt--\r\n\r\n--mixed--\r\n",
+			"From: \r\nMime-Version: 1.0\r\nDate: " + now + "\r\nSubject: \r\nTo: \r\nContent-Type: multipart/mixed;\r\n\tboundary=\"mixed\"; charset=UTF-8\r\n\r\n--mixed\r\nContent-Type: multipart/alternative;\r\n\tboundary=\"alt\"\r\n\r\n--alt\r\nContent-Transfer-Encoding: quoted-printable\r\nContent-Type: text/html; charset=UTF-8\r\n\r\nHTML\r\n--alt--\r\n\r\n--mixed--\r\n",
 			false,
 		},
 		{
@@ -321,7 +329,7 @@ func TestMailYakBuildMime(t *testing.T) {
 			"",
 			"",
 			"",
-			"From: \r\nMime-Version: 1.0\r\nDate: " + now + "\r\nSubject: \r\nTo: \r\nContent-Type: multipart/mixed;\r\n\tboundary=\"mixed\"; charset=UTF-8\r\n\r\n--mixed\r\nContent-Type: multipart/alternative;\r\n\tboundary=\"alt\"\r\n\r\n--alt\r\nContent-Type: text/plain; charset=UTF-8\r\n\r\nPlain\r\n--alt--\r\n\r\n--mixed--\r\n",
+			"From: \r\nMime-Version: 1.0\r\nDate: " + now + "\r\nSubject: \r\nTo: \r\nContent-Type: multipart/mixed;\r\n\tboundary=\"mixed\"; charset=UTF-8\r\n\r\n--mixed\r\nContent-Type: multipart/alternative;\r\n\tboundary=\"alt\"\r\n\r\n--alt\r\nContent-Transfer-Encoding: quoted-printable\r\nContent-Type: text/plain; charset=UTF-8\r\n\r\nPlain\r\n--alt--\r\n\r\n--mixed--\r\n",
 			false,
 		},
 		{