diff --git a/Number_types/include/CGAL/CORE_BigInt.h b/Number_types/include/CGAL/CORE_BigInt.h
index 0e057bcc856..7f1041ea7fa 100644
--- a/Number_types/include/CGAL/CORE_BigInt.h
+++ b/Number_types/include/CGAL/CORE_BigInt.h
@@ -170,6 +170,25 @@ struct Needs_parens_as_product<CORE::BigInt>{
     }
 };
 
+// Benchmark_rep specialization 
+template<>
+class Benchmark_rep< CORE::BigInt > {
+    const CORE::BigInt& t;
+public:
+    //! initialize with a const reference to \a t.
+    Benchmark_rep( const CORE::BigInt& tt) : t(tt) {}
+    //! perform the output, calls \c operator\<\< by default.
+    std::ostream& operator()( std::ostream& out) const { 
+            out << t;
+            return out;
+    }
+    
+    static std::string get_benchmark_name() {
+        return "Integer";
+    }
+};
+
+
 CGAL_END_NAMESPACE
 
 //since types are included by CORE_coercion_traits.h:
diff --git a/Number_types/include/CGAL/CORE_BigRat.h b/Number_types/include/CGAL/CORE_BigRat.h
index d1a9872ab8a..b9aa7b420c6 100644
--- a/Number_types/include/CGAL/CORE_BigRat.h
+++ b/Number_types/include/CGAL/CORE_BigRat.h
@@ -231,6 +231,24 @@ public:
     }
 };
 
+// Benchmark_rep specialization 
+template<>
+class Benchmark_rep< CORE::BigRat > {
+    const CORE::BigRat& t;
+public:
+    //! initialize with a const reference to \a t.
+    Benchmark_rep( const CORE::BigRat& tt) : t(tt) {}
+    //! perform the output, calls \c operator\<\< by default.
+    std::ostream& operator()( std::ostream& out) const { 
+            out << "Rational(" << numerator(t) << "," << denominator(t) << ")";
+            return out;
+    }
+    
+    static std::string get_benchmark_name() {
+        return "Rational";
+    }
+};
+
 CGAL_END_NAMESPACE
 
 //since types are included by CORE_coercion_traits.h:
diff --git a/Number_types/include/CGAL/leda_rational.h b/Number_types/include/CGAL/leda_rational.h
index 097482a0ff9..1ccc5120ad9 100644
--- a/Number_types/include/CGAL/leda_rational.h
+++ b/Number_types/include/CGAL/leda_rational.h
@@ -276,6 +276,26 @@ public:
     }
 };
 
+template < >
+class Benchmark_rep< leda_rational > {
+    const leda_rational& t;
+public:
+    //! initialize with a const reference to \a t.
+    Benchmark_rep( const leda_rational& tt) : t(tt) {}
+    //! perform the output, calls \c operator\<\< by default.
+    std::ostream& operator()( std::ostream& out) const { 
+            return 
+                out << "Rational(" << t.numerator() << "," 
+                    << t.denominator() << ")";
+    }
+
+    static std::string get_benchmark_name() {
+        return "Rational";
+    }
+
+};
+
+
 CGAL_END_NAMESPACE
 
 // Unary + is missing for leda::rational