diff --git a/zilti/build/chicken-build-system.scm b/zilti/build/chicken-build-system.scm
index fb2bf35..c217aba 100644
--- a/zilti/build/chicken-build-system.scm
+++ b/zilti/build/chicken-build-system.scm
@@ -44,7 +44,7 @@
   (setenv "CHICKEN_INSTALL_REPOSITORY"
           (string-append (assoc-ref outputs "out") "/var/lib/chicken/11/"))
   (setenv "CHICKEN_INSTALL_PREFIX"
-          (string-append (assoc-ref outputs "out") "/bin/"))
+          (assoc-ref outputs "out"))
   (setenv "CHICKEN_REPOSITORY_PATH"
           (string-append (getenv "CHICKEN_REPOSITORY_PATH")
                          ":" (getenv "CHICKEN_INSTALL_REPOSITORY")))