diff --git a/src/obi_ecopcr.c b/src/obi_ecopcr.c
index 0b6d2fb..c732361 100755
--- a/src/obi_ecopcr.c
+++ b/src/obi_ecopcr.c
@@ -14,6 +14,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include <getopt.h>
+#include <math.h>
 
 #include "libecoPCR/ecoPCR.h"
 #include "libecoPCR/libthermo/nnparams.h"
@@ -426,9 +427,9 @@ static int print_seq(Obiview_p i_view, Obiview_p o_view,
 	tm2=nparam_CalcTwoTM(tparm,oligo2,primer2,o2->patlen) - 273.15;
 	//tm = (tm1 < tm2) ? tm1:tm2;
 
-	if isnan(tm1)
+	if (isnan(tm1))
 		tm1 = OBIFloat_NA;
-	if isnan(tm2)
+	if (isnan(tm2))
 		tm2 = OBIFloat_NA;
 
 	// Get the taxon structure