diff --git a/Makefile b/Makefile
index 91b5394..f26d056 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@
 all: $(PROGRAMS)
 
 nlsr: $(NLSR_SRCS)
-	$(CC) $(CFLAGS) $(NLSR_SRCS) -o nlsr $(LIBS)
+	$(CC) $(CFLAGS) $(NLSR_SRCS) -o nlsr $(LIBS) -lm
 
 install: $(PROGRAMS)
 	cp $(PROGRAMS) $(INSTALL_PATH)