diff --git a/collects/r6rs/private/readtable.ss b/collects/r6rs/private/readtable.ss
index f86cfb91d3..a8a518b1cd 100644
--- a/collects/r6rs/private/readtable.ss
+++ b/collects/r6rs/private/readtable.ss
@@ -447,7 +447,7 @@
                 (bytes->string/utf-8
                  (car (or (if (string=? prefix "\\")
                               (regexp-match #px"^x[0-9a-fA-F]+;(?:\\\\x[0-9a-fA-F]+;|[^\\\\\\s\\[\\]()#\";,'`])*" port)
-                              (regexp-match #px"^(?:\\\\x[0-9a-fA-F]+;|[^\\\\\\s\\[\\]()#\";,'`])*" port))
+                              (regexp-match #px"^(?:#[xXdDbBoOeEiI])*(?:\\\\x[0-9a-fA-F]+;|[^\\\\\\s\\[\\]()#\";,'`])*" port))
                           '(#"")))))])
     (cond
      [(regexp-match? #rx"^[a-zA-Z!$%&*/:<=>?^_~][a-zA-Z0-9+!$%&*/:<=>?^_~.@-]*$" thing)
diff --git a/collects/tests/r6rs/reader.ss b/collects/tests/r6rs/reader.ss
index 028d2515e6..12c550164e 100644
--- a/collects/tests/r6rs/reader.ss
+++ b/collects/tests/r6rs/reader.ss
@@ -71,7 +71,9 @@
      "#O+23761236721631263126371263712"
      "#O+0"
      "#O-0"
-     "#O0")
+     "#O0"
+     "#i#xf/e"
+     "#x#if/e")
     
     (test (read (open-string-input-port "#\\nul")) 
           (integer->char #x0))