diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index a7f9ac469..b117c0b37 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -73,8 +73,6 @@ add_library(oqs kem/kem.c
                 ${SIG_OBJS}
                 sig_stfl/sig_stfl.c
                 ${SIG_STFL_OBJS}
-                sig_stfl/sig_stfl.c
-                ${SIG_STFL_OBJS}
                 ${COMMON_OBJS})
 
 # Internal library to be used only by test programs