diff --git a/scheme/read.sld b/scheme/read.sld
index ec36eb86..aa399f10 100644
--- a/scheme/read.sld
+++ b/scheme/read.sld
@@ -313,19 +313,25 @@
                    (parse fp '() (cons #f toks) all? #f parens ptbl)
                    #f))
               ;; Numbers
-;; TODO: #b (binary), #o (octal), #d (decimal), and #x (hexadecimal)
               ((eq? #\e next-c)
-               (parse-number 
-                 fp toks all? parens ptbl 
+               (parse-number fp toks all? parens ptbl 
                  10 (lambda (num)
                       (exact
                         (parse-atom num)))))
               ((eq? #\i next-c)
-               (parse-number 
-                 fp toks all? parens ptbl 
+               (parse-number fp toks all? parens ptbl 
                  10 (lambda (num)
                       (inexact
                         (parse-atom num)))))
+              ((eq? #\b next-c)
+               (parse-number fp toks all? parens ptbl 
+                 2 (lambda (num) (list->string num))))
+              ((eq? #\o next-c)
+               (parse-number fp toks all? parens ptbl 
+                 8 (lambda (num) (list->string num))))
+              ((eq? #\x next-c)
+               (parse-number fp toks all? parens ptbl 
+                 16 (lambda (num) (list->string num))))
               ;; Vector
               ((eq? #\( next-c)
                (let ((sub (parse fp '() '() #t #f (+ parens 1) ptbl))
@@ -467,11 +473,14 @@
 
 (define (parse-number fp toks all? parens ptbl base tok->num)
 ;  (parse-number-rec base fp '() ptbl))
-  (let ((num (parse-number-rec 10 fp '() ptbl)))
+  (let ((num (parse-number-rec base fp '() ptbl)))
     ;(write `(DEBUG2 ,num ,(string? num)))
     (cond
       ((and (not (null? num))
-            (token-numeric? num))
+            (or (token-numeric? num)
+                (and (> (length num) 0)
+                     (= base 16)
+                     (hex-digit? (car num)))))
        (let ((result (tok->num num)))
          (if all?
              (parse fp '() (cons result toks) all? #f parens ptbl)
@@ -488,11 +497,24 @@
     (cond
       ((sign? c) (next c))
       ((eq? #\. c) (next c))
-      ((char-numeric? c) (next c))
+      ((char-numeric? c) 
+       (if (or (and (= base 2) (char>? c #\1))
+               (and (= base 8) (char>? c #\7)))
+           (parse-error
+             "Illegal digit"
+             (in-port:get-lnum ptbl)
+             (in-port:get-cnum ptbl)))
+       (next c))
+      ((and (= base 16) (hex-digit? c))
+       (next c))
       (else
         ;; We are done parsing a number
         (in-port:set-buf! ptbl c) ;; rebuffer unprocessed char
         (reverse tok))))) ;; Return token
+
+(define (hex-digit? c)
+  (or (and (char>=? c #\a) (char<=? c #\f))
+      (and (char>=? c #\A) (char<=? c #\F))))
 ;;;;;
   
 ;; Main lexer/parser