diff --git a/C/c_interface.c b/C/c_interface.c
index 5301ee434..16aeffa98 100755
--- a/C/c_interface.c
+++ b/C/c_interface.c
@@ -385,6 +385,7 @@ X_API Bool    STD_PROTO(YAP_IsNonVarTerm,(Term));
 X_API Bool    STD_PROTO(YAP_IsIntTerm,(Term));
 X_API Bool    STD_PROTO(YAP_IsLongIntTerm,(Term));
 X_API Bool    STD_PROTO(YAP_IsBigNumTerm,(Term));
+X_API Bool    STD_PROTO(YAP_IsRationalTerm,(Term));
 X_API Bool    STD_PROTO(YAP_IsFloatTerm,(Term));
 X_API Bool    STD_PROTO(YAP_IsDbRefTerm,(Term));
 X_API Bool    STD_PROTO(YAP_IsAtomTerm,(Term));
@@ -392,8 +393,10 @@ X_API Bool    STD_PROTO(YAP_IsPairTerm,(Term));
 X_API Bool    STD_PROTO(YAP_IsApplTerm,(Term));
 X_API Term    STD_PROTO(YAP_MkIntTerm,(Int));
 X_API Term    STD_PROTO(YAP_MkBigNumTerm,(void *));
+X_API Term    STD_PROTO(YAP_MkRationalTerm,(void *));
 X_API Int     STD_PROTO(YAP_IntOfTerm,(Term));
 X_API void    STD_PROTO(YAP_BigNumOfTerm,(Term, void *));
+X_API void    STD_PROTO(YAP_RationalOfTerm,(Term, void *));
 X_API Term    STD_PROTO(YAP_MkFloatTerm,(flt));
 X_API flt     STD_PROTO(YAP_FloatOfTerm,(Term));
 X_API Term    STD_PROTO(YAP_MkAtomTerm,(Atom));
@@ -601,7 +604,29 @@ X_API Bool
 YAP_IsBigNumTerm(Term t)
 {
 #if USE_GMP
-  return IsBigIntTerm(t);
+  CELL *pt;
+  if (IsVarTerm(t))
+    return FALSE;
+  if (!IsBigIntTerm(t))
+    return FALSE;
+  pt = RepAppl(t);
+  return pt[1] == BIG_INT;
+#else
+  return FALSE;
+#endif
+}
+
+X_API Bool 
+YAP_IsRationalTerm(Term t)
+{
+#if USE_GMP
+  CELL *pt;
+  if (IsVarTerm(t))
+    return FALSE;
+  if (!IsBigIntTerm(t))
+    return FALSE;
+  pt = RepAppl(t);
+  return pt[1] == BIG_RATIONAL;
 #else
   return FALSE;
 #endif
@@ -698,6 +723,33 @@ YAP_BigNumOfTerm(Term t, void *b)
 #endif /* USE_GMP */
 }
 
+X_API Term 
+YAP_MkRationalTerm(void *big)
+{
+#if USE_GMP
+  Term I;
+  BACKUP_H();
+  I = Yap_MkBigRatTerm((MP_RAT *)big);
+  RECOVER_H();
+  return I;
+#else
+  return TermNil;
+#endif /* USE_GMP */
+}
+
+X_API void
+YAP_RationalOfTerm(Term t, void *b)
+{
+#if USE_GMP
+  MP_RAT *br = (MP_RAT *)b;
+  if (IsVarTerm(t))
+    return;
+  if (!IsBigIntTerm(t))
+    return;
+  mpq_set(br,Yap_BigRatOfTerm(t));
+#endif /* USE_GMP */
+}
+
 X_API Term 
 YAP_MkBlobTerm(unsigned int sz)
 {
diff --git a/include/YapInterface.h b/include/YapInterface.h
index 12860e4e4..ca720aab5 100755
--- a/include/YapInterface.h
+++ b/include/YapInterface.h
@@ -103,6 +103,9 @@ extern X_API YAP_Bool PROTO(YAP_IsLongIntTerm,(YAP_Term));
 /*  YAP_Bool IsBigNumTerm(YAP_Term)  */
 extern X_API YAP_Bool PROTO(YAP_IsBigNumTerm,(YAP_Term));
 
+/*  YAP_Bool IsRationalTerm(YAP_Term)  */
+extern X_API YAP_Bool PROTO(YAP_IsRationalTerm,(YAP_Term));
+
 /*  YAP_Bool IsFloatTerm(YAP_Term)  */
 extern X_API YAP_Bool PROTO(YAP_IsFloatTerm,(YAP_Term));
 
@@ -124,12 +127,18 @@ extern X_API YAP_Term PROTO(YAP_MkIntTerm,(YAP_Int));
 /*    Term MkBigNumTerm(void *)  */
 extern X_API YAP_Term PROTO(YAP_MkBigNumTerm,(void *));
 
+/*    Term MkRationalTerm(void *)  */
+extern X_API YAP_Term PROTO(YAP_MkRationalTerm,(void *));
+
 /*    YAP_Int  IntOfTerm(Term) */
 extern X_API YAP_Int PROTO(YAP_IntOfTerm,(YAP_Term));
 
 /*    void *  BigNumOfTerm(Term) */
 extern X_API void *PROTO(YAP_BigNumOfTerm,(YAP_Term, void *));
 
+/*    void *  RationalOfTerm(Term) */
+extern X_API void *PROTO(YAP_RationalOfTerm,(YAP_Term, void *));
+
 /*    Term MkFloatTerm(YAP_Float)  */
 extern X_API YAP_Term PROTO(YAP_MkFloatTerm,(YAP_Float));
 
diff --git a/packages/PLStream/pl-yap.c b/packages/PLStream/pl-yap.c
index 9b59fb4f9..432578433 100755
--- a/packages/PLStream/pl-yap.c
+++ b/packages/PLStream/pl-yap.c
@@ -190,6 +190,12 @@ valueExpression(term_t t, Number r ARG_LD)
     YAP_BigNumOfTerm(t0, &r->value.mpz);
     return 1;
   }
+  if (YAP_IsRationalTerm(t0)) {
+    r->type = V_MPQ;
+    mpq_init(&r->value.mpq);
+    YAP_RationalOfTerm(t0, &r->value.mpq);
+    return 1;
+  }
 #endif
   return 0;
 }