diff --git a/mats/format.ms b/mats/format.ms
index b0e4762fd..d8a07ec3f 100644
--- a/mats/format.ms
+++ b/mats/format.ms
@@ -1461,8 +1461,10 @@
 
 (mat format-slib17 ; variable parameter
   (equal? (format "~va" 10 "abc") "abc       ")
+  (equal? (format "~Va" 10 "abc") "abc       ") ; Let's test uppercase V too.
  ; changed 42 to #\* below
   (equal? (format "~v,,,va" 10 #\* "abc") "abc*******")
+  (equal? (format "~V,,,Va" 10 #\* "abc") "abc*******") ; Let's test uppercase V too.
 )
 
 (mat format-slib18 ; number of remaining arguments as parameter
diff --git a/s/format.ss b/s/format.ss
index be09796f3..c4a5cd860 100644
--- a/s/format.ss
+++ b/s/format.ss
@@ -213,7 +213,7 @@
                 [(#\,) (state s4-comma () (fx+ i 1) b '(#f))]
                 [(#\') (state s4-quote () (fx+ i 1) b '())]
                 [(#\#) (state s4-after-param () (fx+ i 1) b '(hash))]
-                [(#\v) (state s4-after-param ([nargs (bump nargs 1)]) (fx+ i 1) b '(v))]
+                [(#\v #\V) (state s4-after-param ([nargs (bump nargs 1)]) (fx+ i 1) b '(v))]
                 [else (state s5 () i b '())]))))
         (define s4-sign
           (state lambda (i b p* bp)
@@ -253,7 +253,7 @@
                 [(#\,) (state s4-comma () (fx+ i 1) b (cons #f p*))]
                 [(#\') (state s4-quote () (fx+ i 1) b p*)]
                 [(#\#) (state s4-after-param () (fx+ i 1) b (cons 'hash p*))]
-                [(#\v) (state s4-after-param ([nargs (bump nargs 1)]) (fx+ i 1) b (cons 'v p*))]
+                [(#\v #\V) (state s4-after-param ([nargs (bump nargs 1)]) (fx+ i 1) b (cons 'v p*))]
                 [else (state s5 () i b (reverse (cons #f p*)))]))))
         (define s5
           (state lambda (i b p*)