diff --git a/src/pkg/sort/sort.go b/src/pkg/sort/sort.go
index 067d27901e..0a4a4375f0 100644
--- a/src/pkg/sort/sort.go
+++ b/src/pkg/sort/sort.go
@@ -6,6 +6,8 @@
 // collections.
 package sort
 
+import "math"
+
 // A type, typically a collection, that satisfies sort.Interface can be
 // sorted by the routines in this package.  The methods require that the
 // elements of the collection be enumerated by an integer index.
@@ -167,7 +169,7 @@ func (p IntSlice) Sort() { Sort(p) }
 type Float64Slice []float64
 
 func (p Float64Slice) Len() int           { return len(p) }
-func (p Float64Slice) Less(i, j int) bool { return p[i] < p[j] }
+func (p Float64Slice) Less(i, j int) bool { return p[i] < p[j] || math.IsNaN(p[i]) && !math.IsNaN(p[j]) }
 func (p Float64Slice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
 
 // Sort is a convenience method.
diff --git a/src/pkg/sort/sort_test.go b/src/pkg/sort/sort_test.go
index 64d486b759..5007a92a56 100644
--- a/src/pkg/sort/sort_test.go
+++ b/src/pkg/sort/sort_test.go
@@ -6,6 +6,7 @@ package sort_test
 
 import (
 	"fmt"
+	"math"
 	"rand"
 	. "sort"
 	"strconv"
@@ -13,7 +14,7 @@ import (
 )
 
 var ints = [...]int{74, 59, 238, -784, 9845, 959, 905, 0, 0, 42, 7586, -5467984, 7586}
-var float64s = [...]float64{74.3, 59.0, 238.2, -784.0, 2.3, 9845.768, -959.7485, 905, 7.8, 7.8}
+var float64s = [...]float64{74.3, 59.0, math.Inf(1), 238.2, -784.0, 2.3, math.NaN(), math.NaN(), math.Inf(-1), 9845.768, -959.7485, 905, 7.8, 7.8}
 var strings = [...]string{"", "Hello", "foo", "bar", "foo", "f00", "%*&^*&^&", "***"}
 
 func TestSortIntSlice(t *testing.T) {