diff --git a/bin/Makefile b/bin/Makefile
index 8395138..9f6baf6 100644
--- a/bin/Makefile
+++ b/bin/Makefile
@@ -7,12 +7,12 @@ all: ikarus
 
 ikarus: ikarus-collect.o ikarus-runtime.o ikarus-main.o ikarus-fasl.o \
   ikarus-exec.o ikarus-print.o ikarus-enter.o ikarus-symbol-table.o  \
-  ikarus-weak-pairs.o ikarus-numerics.o
+  ikarus-weak-pairs.o ikarus-numerics.o ikarus-flonums.o
 	$(CC)  $(LDFLAGS) -o ikarus \
 	ikarus-main.o ikarus-runtime.o \
 	ikarus-fasl.o ikarus-exec.o ikarus-print.o ikarus-enter.o \
 	ikarus-symbol-table.o ikarus-collect.o ikarus-weak-pairs.o \
-	ikarus-numerics.o
+	ikarus-numerics.o ikarus-flonums.o
 
 ikarus-main.o: ikarus-main.c ikarus.h
 	$(CC) $(CFLAGS) -c ikarus-main.c
@@ -45,6 +45,9 @@ ikarus-symbol-table.o: ikarus-symbol-table.c ikarus.h
 ikarus-numerics.o: ikarus-numerics.c ikarus.h
 	$(CC) $(CFLAGS) -c ikarus-numerics.c
 
+ikarus-flonums.o: ikarus-flonums.c ikarus.h
+	$(CC) $(CFLAGS) -c ikarus-flonums.c
+
 ikarus.h: ikarus-data.h
 	touch ikarus.h
 
diff --git a/bin/ikarus b/bin/ikarus
index b07b1fd..e4791ef 100755
Binary files a/bin/ikarus and b/bin/ikarus differ
diff --git a/bin/ikarus-data.h b/bin/ikarus-data.h
index b3f449b..b45f849 100644
--- a/bin/ikarus-data.h
+++ b/bin/ikarus-data.h
@@ -196,4 +196,9 @@
 #define disp_bignum_data wordsize
 #define off_bignum_data (disp_bignum_data - vector_tag)
 
+#define flonum_tag  ((ikp)0xFF)
+#define flonum_size         16
+#define disp_flonum_data     8
+#define off_flonum_data (disp_flonum_data - vector_tag)
+
 #endif
diff --git a/src/ikarus.boot b/src/ikarus.boot
index 7109030..4a10504 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/libnumerics.ss b/src/libnumerics.ss
index 6299fcc..381192f 100644
--- a/src/libnumerics.ss
+++ b/src/libnumerics.ss
@@ -1,4 +1,23 @@
 
+(let ()
+  (define (flonum? x)
+    (foreign-call "ikrt_is_flonum" x))
+  (define (flonum->string x)
+    (or (foreign-call "ikrt_flonum_to_string" x)
+        (error 'flonum->string "~s is not a flonum" x)))
+  (define (string->flonum x)
+    (cond
+      [(string? x) (foreign-call "ikrt_string_to_flonum" x)]
+      [else 
+       (error 'string->flonum "~s is not a string" x)]))
+
+  (primitive-set! 'flonum? flonum?)
+  (primitive-set! 'flonum->string flonum->string)
+  (primitive-set! 'string->flonum string->flonum)
+)
+
+
+
 (let ()
   
   (define bignum? 
diff --git a/src/makefile.ss b/src/makefile.ss
index a01af5d..b79bc60 100755
--- a/src/makefile.ss
+++ b/src/makefile.ss
@@ -92,6 +92,8 @@
     char-downcase max min complex? real? rational? 
     exact? inexact? integer?
     string->number
+
+    flonum? flonum->string string->flonum
     ))
 
 (define system-primitives