diff --git a/Code/DataStructs/ExplicitBitVect.cpp b/Code/DataStructs/ExplicitBitVect.cpp
index ea72e42a7..84690cc84 100644
--- a/Code/DataStructs/ExplicitBitVect.cpp
+++ b/Code/DataStructs/ExplicitBitVect.cpp
@@ -1,6 +1,7 @@
 // $Id$
 //
 // Copyright (c) 2001-2008 greg Landrum and Rational Discovery LLC
+//  Copyright (c) 2014, Novartis Institutes for BioMedical Research Inc.
 //
 //  @@ All Rights Reserved @@
 //  This file is part of the RDKit.
@@ -111,6 +112,24 @@ ExplicitBitVect::ExplicitBitVect(const char *data,const unsigned int dataLen)
     return(ans);
   };
   
+  ExplicitBitVect& ExplicitBitVect::operator^= (const ExplicitBitVect &other) {
+    *(dp_bits) ^= *(other.dp_bits);
+    d_numOnBits=dp_bits->count();
+    return *this;
+  };
+
+  ExplicitBitVect& ExplicitBitVect::operator&= (const ExplicitBitVect &other) {
+    *(dp_bits) &= *(other.dp_bits);
+    d_numOnBits=dp_bits->count();
+    return *this;
+  };
+
+  ExplicitBitVect& ExplicitBitVect::operator|= (const ExplicitBitVect &other) {
+    *(dp_bits) |= *(other.dp_bits);
+    d_numOnBits=dp_bits->count();
+    return *this;
+  };
+
   ExplicitBitVect ExplicitBitVect::operator~ () const {
     ExplicitBitVect ans(d_size);
     *(ans.dp_bits) = ~(*dp_bits);
@@ -118,6 +137,24 @@ ExplicitBitVect::ExplicitBitVect(const char *data,const unsigned int dataLen)
     return(ans);
   };
 
+  ExplicitBitVect& ExplicitBitVect::operator+= (const ExplicitBitVect &other) {
+    dp_bits->resize(d_size+other.d_size);
+    unsigned int original_size = d_size;
+    d_size = dp_bits->size();
+    for(unsigned i=0;i<other.d_size;i++){
+      if(other[i]){
+        setBit(i+original_size);
+      }
+    }
+    d_numOnBits=dp_bits->count();
+    return *this;
+  };
+
+  ExplicitBitVect ExplicitBitVect::operator+ (const ExplicitBitVect &other) const {
+    ExplicitBitVect ans(*this);
+    return ans+=other;
+  };
+
   unsigned int ExplicitBitVect::getNumBits() const {
     return d_size;
   };
diff --git a/Code/DataStructs/ExplicitBitVect.h b/Code/DataStructs/ExplicitBitVect.h
index 7a021d04d..957572c0e 100644
--- a/Code/DataStructs/ExplicitBitVect.h
+++ b/Code/DataStructs/ExplicitBitVect.h
@@ -1,5 +1,6 @@
 //
-// Copyright (c) 2003-2008 greg Landrum and Rational Discovery LLC
+// Copyright (c) 2003-208 greg Landrum and Rational Discovery LLC
+//  Copyright (c) 2014, Novartis Institutes for BioMedical Research Inc.
 //
 //  @@ All Rights Reserved @@
 //  This file is part of the RDKit.
@@ -47,13 +48,21 @@ public:
   ExplicitBitVect operator& (const ExplicitBitVect &other) const;
   ExplicitBitVect operator| (const ExplicitBitVect &other) const;
   ExplicitBitVect operator~ () const;
+  /* concatenate two ExplicitBitVects */
+  ExplicitBitVect operator+ (const ExplicitBitVect &other) const;
+
+  ExplicitBitVect& operator^= (const ExplicitBitVect &other);
+  ExplicitBitVect& operator&= (const ExplicitBitVect &other);
+  ExplicitBitVect& operator|= (const ExplicitBitVect &other);
+  /* concatenate two ExplicitBitVects */
+  ExplicitBitVect& operator+= (const ExplicitBitVect &other);
+
   unsigned int getNumBits() const;
   unsigned int getNumOnBits() const;
   unsigned int getNumOffBits() const;
 
   void getOnBits (IntVect& v) const;
 
-  // FIX: complete these
   void clearBits() { dp_bits->reset(); };
   std::string toString() const;
   
diff --git a/Code/DataStructs/Wrap/wrap_ExplicitBV.cpp b/Code/DataStructs/Wrap/wrap_ExplicitBV.cpp
index ad4dcadb7..78e68e4f3 100644
--- a/Code/DataStructs/Wrap/wrap_ExplicitBV.cpp
+++ b/Code/DataStructs/Wrap/wrap_ExplicitBV.cpp
@@ -88,9 +88,11 @@ struct EBV_wrapper {
     .def(python::self & python::self)
     .def(python::self | python::self)
     .def(python::self ^ python::self)
+    .def(python::self + python::self)
     .def(~python::self)
     .def(python::self == python::self)
     .def(python::self != python::self)
+    .def(python::self += python::self)
 
     .def_pickle(ebv_pickle_suite())
   ;
diff --git a/Code/DataStructs/testDatastructs.cpp b/Code/DataStructs/testDatastructs.cpp
index 5a6a667ff..661de7a50 100644
--- a/Code/DataStructs/testDatastructs.cpp
+++ b/Code/DataStructs/testDatastructs.cpp
@@ -1,6 +1,6 @@
 // $Id$
 //
-//  Copyright (C) 2001-2010 Greg Landrum and Rational Discovery LLC
+//  Copyright (C) 2001-2014 Greg Landrum and Rational Discovery LLC
 //
 //  @@ All Rights Reserved @@
 //  This file is part of the RDKit.
@@ -1296,6 +1296,17 @@ void test13BitVectAllOnes() {
   }
 }
 
+void test18BitVectConcatenation() {
+ {
+   ExplicitBitVect bv(32, false);
+   ExplicitBitVect bv2(32, true);
+   ExplicitBitVect bv3 = bv + bv2;
+   TEST_ASSERT(bv3.getNumBits() == 64);
+   TEST_ASSERT(bv3.getNumOnBits() == 32);
+   TEST_ASSERT(bv3.getNumOffBits() == 32);
+  }
+}
+
 int main(){
   RDLog::InitLogs();
   try{
@@ -1363,6 +1374,9 @@ int main(){
   BOOST_LOG(rdInfoLog) << " Test BitVect with all ones -------------------------------" << std::endl;
   test13BitVectAllOnes();
 
+  BOOST_LOG(rdInfoLog) << " Test Explicit BitVects: Concatenation Operation  -------------------------------" << std::endl;
+  test18BitVectConcatenation();
+
   return 0;
   
 }