diff --git a/program/function_definition.go b/program/function_definition.go
index 848bf2775..eed041fe5 100644
--- a/program/function_definition.go
+++ b/program/function_definition.go
@@ -126,6 +126,7 @@ var builtInFunctionDefinitions = map[string][]string{
 		"double log(double) -> math.Log",
 		"double log10(double) -> math.Log10",
 		"double pow(double, double) -> math.Pow",
+		"double round(double) -> math.Round",
 		"double sin(double) -> math.Sin",
 		"double sinh(double) -> math.Sinh",
 		"double sqrt(double) -> math.Sqrt",
diff --git a/tests/math.c b/tests/math.c
index 4f7675501..bbda2d36c 100644
--- a/tests/math.c
+++ b/tests/math.c
@@ -11,7 +11,7 @@ unsigned long long ullmax = 18446744073709551615ull;
 
 int main()
 {
-  plan(359);
+  plan(372);
 
   // Note: There are some tests that must be disabled because they return
   // different values under different compilers. See the comment surrounding the
@@ -400,6 +400,21 @@ int main()
   is_nan(pow(-INFINITY, NAN));
   is_nan(pow(NAN, NAN));
 
+  diag("round");
+  is_eq(round(0), 0);
+  is_eq(round(1), 1);
+  is_eq(round(-1), -1);
+  is_eq(round(0.5), 1);
+  is_eq(round(-0.5), -1);
+  is_eq(round(0.4), 0);
+  is_negzero(round(-0.4));
+  is_eq(round(1.23e300), 1.23e300);
+  is_eq(round(-1.23e300), -1.23e300);
+  is_eq(round(M_PI), 3);
+  is_inf(round(INFINITY), 1);
+  is_inf(round(-INFINITY), -1);
+  is_nan(round(NAN));
+
   diag("sin");
   is_eq(sin(0), 0);
   is_eq(sin(1), 0.84147098480789650488);