diff --git a/module/srfi/srfi-111.scm b/module/srfi/srfi-111.scm
index 3d3cd896b..2db34ffc4 100644
--- a/module/srfi/srfi-111.scm
+++ b/module/srfi/srfi-111.scm
@@ -32,6 +32,6 @@
   (lambda (box port)
     (display "#<box " port)
     (display (number->string (object-address box) 16) port)
-    (display " value: ")
+    (display " value: " port)
     (write (unbox box) port)
     (display ">" port)))
diff --git a/test-suite/tests/srfi-111.test b/test-suite/tests/srfi-111.test
index e2d76c6d5..8d56ea907 100644
--- a/test-suite/tests/srfi-111.test
+++ b/test-suite/tests/srfi-111.test
@@ -62,4 +62,8 @@
              (not (equal? box1 box2))
              ;; Guile extension, not guaranteed by SRFI-111.
              (begin (set-box! box2 (string #\f #\o #\o))
-                    (equal? box1 box2)))))))
+                    (equal? box1 box2))))))
+
+  (pass-if "box printer"
+    (integer? (string-contains (call-with-output-string (lambda (o) (display (box 1) o)))
+                               "value: 1"))))