diff --git a/src/mimemessage.cpp b/src/mimemessage.cpp
index bb64906..556132e 100644
--- a/src/mimemessage.cpp
+++ b/src/mimemessage.cpp
@@ -106,6 +106,11 @@ void MimeMessage::addPart(MimePart *part)
     };
 }
 
+void MimeMessage::setInReplyTo(const QString& inReplyTo)
+{
+    mInReplyTo = inReplyTo;
+}
+
 void MimeMessage::setHeaderEncoding(MimePart::Encoding hEnc)
 {
     this->hEncoding = hEnc;
@@ -252,6 +257,11 @@ QString MimeMessage::toString()
 
     mime += "\r\n";
     mime += "MIME-Version: 1.0\r\n";
+    if (!mInReplyTo.isEmpty())
+    {
+        mime += "In-Reply-To: <" + mInReplyTo + ">\r\n";
+        mime += "References: <" + mInReplyTo + ">\r\n";
+    }
     mime += QString("Date: %1\r\n").arg(QDateTime::currentDateTime().toString(Qt::RFC2822Date));
 
     mime += content->toString();
diff --git a/src/mimemessage.h b/src/mimemessage.h
index 18b4ec3..36586f4 100644
--- a/src/mimemessage.h
+++ b/src/mimemessage.h
@@ -54,6 +54,8 @@ public:
     void setSubject(const QString & subject);
     void addPart(MimePart* part);
 
+    void setInReplyTo(const QString& inReplyTo);
+
     void setHeaderEncoding(MimePart::Encoding);
 
     const EmailAddress & getSender() const;
@@ -79,6 +81,7 @@ protected:
     EmailAddress* sender;
     QList<EmailAddress*> recipientsTo, recipientsCc, recipientsBcc;
     QString subject;
+    QString mInReplyTo;
     MimePart *content;
     bool autoMimeContentCreated;