diff -r 131f8c8eb722 src/cmd/gofmt/testdata/import.golden
--- a/src/cmd/gofmt/testdata/import.golden	Wed Mar 06 16:52:03 2013 -0800
+++ b/src/cmd/gofmt/testdata/import.golden	Thu Mar 07 14:55:48 2013 +0100
@@ -106,3 +106,13 @@
 	"log" // for Fatal
 	"math"
 )
+
+import (
+	err1 "errors"
+	err2 "errors"
+	"fmt"
+	"io"
+	"os" // os1
+	"os" // os2
+
+)
diff -r 131f8c8eb722 src/cmd/gofmt/testdata/import.input
--- a/src/cmd/gofmt/testdata/import.input	Wed Mar 06 16:52:03 2013 -0800
+++ b/src/cmd/gofmt/testdata/import.input	Thu Mar 07 14:55:48 2013 +0100
@@ -106,3 +106,14 @@
 	"errors"
 	"io" // for Reader
 )
+
+import (
+	"io"
+	"fmt"
+	"fmt"
+	"os" // os1
+	"os" // os2
+	err1 "errors"
+	err2 "errors"
+	"fmt"
+)
diff -r 131f8c8eb722 src/pkg/go/ast/import.go
--- a/src/pkg/go/ast/import.go	Wed Mar 06 16:52:03 2013 -0800
+++ b/src/pkg/go/ast/import.go	Thu Mar 07 14:55:48 2013 +0100
@@ -5,6 +5,7 @@
 package ast
 
 import (
+	"fmt"
 	"go/token"
 	"sort"
 	"strconv"
@@ -26,18 +27,55 @@
 		}
 
 		// Identify and sort runs of specs on successive lines.
+		var specs []Spec
 		i := 0
 		for j, s := range d.Specs {
 			if j > i && fset.Position(s.Pos()).Line > 1+fset.Position(d.Specs[j-1].End()).Line {
 				// j begins a new run.  End this one.
-				sortSpecs(fset, f, d.Specs[i:j])
+				run := d.Specs[i:j]
+				run = removeDuplicateImports(run)
+				sortSpecs(fset, f, run)
+				specs = append(specs, run...)
 				i = j
 			}
 		}
-		sortSpecs(fset, f, d.Specs[i:])
+		run := d.Specs[i:]
+		run = removeDuplicateImports(run)
+		sortSpecs(fset, f, run)
+		specs = append(specs, run...)
+		d.Specs = specs
 	}
 }
 
+// Returns the unique ID of the ImportSpec
+func importSpecID(s *ImportSpec) string {
+	return fmt.Sprintf("(%v)(%v)", s.Name, s.Path.Value)
+}
+
+func removeDuplicateImports(specs []Spec) []Spec {
+	var filtered []Spec
+	ids := make(map[string]bool)
+
+	for _, spec := range specs {
+		imp := spec.(*ImportSpec)
+
+		var id = ""
+		if imp.Doc == nil && imp.Comment == nil {
+			id = importSpecID(imp)
+			if ids[id] {
+				continue
+			}
+		}
+
+		filtered = append(filtered, imp)
+		if id != "" {
+			ids[id] = true
+		}
+	}
+
+	return filtered
+}
+
 func importPath(s Spec) string {
 	t, err := strconv.Unquote(s.(*ImportSpec).Path.Value)
 	if err == nil {