diff --git a/ChangeLog b/ChangeLog
index 3a8fe0b..f2a2318 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -20,6 +20,7 @@
  * IntaRNA/Interaction
    * Seed::operator"<"
      * BUGFIX: less-than check fixed
+   + operator<<(Boundary)
  * IntaRNA/PredictorMfe :
    * updateOptima() :
      + no interaction update if "n==0"
diff --git a/src/IntaRNA/Interaction.cpp b/src/IntaRNA/Interaction.cpp
index 6a97b06..07d1dc5 100644
--- a/src/IntaRNA/Interaction.cpp
+++ b/src/IntaRNA/Interaction.cpp
@@ -1,7 +1,6 @@
 /*
  * Interaction.cpp
  *
- *  Created on: 14.07.2014
  *      Author: Mmann
  */
 
@@ -27,6 +26,15 @@ operator<<(std::ostream& out, const Interaction::BasePair& bp)
 
 ////////////////////////////////////////////////////////////////////////////
 
+std::ostream&
+operator<<(std::ostream& out, const Interaction::Boundary& b)
+{
+	out <<"("<<b.i1<<":"<<b.i2<<")-("<<b.j1<<","<<b.j2<<")";
+	return out;
+}
+
+////////////////////////////////////////////////////////////////////////////
+
 std::ostream&
 operator<<(std::ostream& out, const Interaction& i)
 {
diff --git a/src/IntaRNA/Interaction.h b/src/IntaRNA/Interaction.h
index 79dc6ae..98bac21 100644
--- a/src/IntaRNA/Interaction.h
+++ b/src/IntaRNA/Interaction.h
@@ -311,7 +311,15 @@ class Interaction {
 	 * @param bp the Interaction base pair object to add
 	 * @return the altered stream out
 	 */
-	friend std::ostream& operator<<(std::ostream& out, const Interaction::BasePair& bp);
+	friend std::ostream& operator<<(std::ostream& out, const BasePair& bp);
+
+	/**
+	 * Prints the interacting boundary to stream
+	 * @param out the ostream to write to
+	 * @param bp the Interaction Boundary object to add
+	 * @return the altered stream out
+	 */
+	friend std::ostream& operator<<(std::ostream& out, const Boundary& bp);
 
 	/**
 	 * Prints the interacting base pairs to stream