diff --git a/internal/imports/fix_test.go b/internal/imports/fix_test.go
index d15b6dd248..fca61568f7 100644
--- a/internal/imports/fix_test.go
+++ b/internal/imports/fix_test.go
@@ -372,7 +372,37 @@ func foo() {
 }
 `,
 	},
+	// Merge import blocks, even when no additions are required.
+	{
+		name: "merge_import_blocks_no_fix",
+		in: `package foo
 
+import (
+	"fmt"
+)
+import "os"
+
+import (
+	"rsc.io/p"
+)
+
+var _, _ = os.Args, fmt.Println
+var _, _ = snappy.ErrCorrupt, p.P
+`,
+		out: `package foo
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/golang/snappy"
+	"rsc.io/p"
+)
+
+var _, _ = os.Args, fmt.Println
+var _, _ = snappy.ErrCorrupt, p.P
+`,
+	},
 	// Delete existing empty import block
 	{
 		name: "delete_empty_import_block",
diff --git a/internal/imports/imports.go b/internal/imports/imports.go
index 82d02f0d3b..9a132cddbb 100644
--- a/internal/imports/imports.go
+++ b/internal/imports/imports.go
@@ -136,6 +136,7 @@ func initialize(filename string, src []byte, opt *Options) ([]byte, *Options, er
 }
 
 func formatFile(fileSet *token.FileSet, file *ast.File, src []byte, adjust func(orig []byte, src []byte) []byte, opt *Options) ([]byte, error) {
+	mergeImports(opt.Env, fileSet, file)
 	sortImports(opt.Env, fileSet, file)
 	imps := astutil.Imports(fileSet, file)
 	var spacesBefore []string // import paths we need spaces before
diff --git a/internal/imports/sortimports.go b/internal/imports/sortimports.go
index 0a156fe2ef..226279471d 100644
--- a/internal/imports/sortimports.go
+++ b/internal/imports/sortimports.go
@@ -58,6 +58,53 @@ func sortImports(env *ProcessEnv, fset *token.FileSet, f *ast.File) {
 	}
 }
 
+// mergeImports merges all the import declarations into the first one.
+// Taken from golang.org/x/tools/ast/astutil.
+func mergeImports(env *ProcessEnv, fset *token.FileSet, f *ast.File) {
+	if len(f.Decls) <= 1 {
+		return
+	}
+
+	// Merge all the import declarations into the first one.
+	var first *ast.GenDecl
+	for i := 0; i < len(f.Decls); i++ {
+		decl := f.Decls[i]
+		gen, ok := decl.(*ast.GenDecl)
+		if !ok || gen.Tok != token.IMPORT || declImports(gen, "C") {
+			continue
+		}
+		if first == nil {
+			first = gen
+			continue // Don't touch the first one.
+		}
+		// We now know there is more than one package in this import
+		// declaration. Ensure that it ends up parenthesized.
+		first.Lparen = first.Pos()
+		// Move the imports of the other import declaration to the first one.
+		for _, spec := range gen.Specs {
+			spec.(*ast.ImportSpec).Path.ValuePos = first.Pos()
+			first.Specs = append(first.Specs, spec)
+		}
+		f.Decls = append(f.Decls[:i], f.Decls[i+1:]...)
+		i--
+	}
+}
+
+// declImports reports whether gen contains an import of path.
+// Taken from golang.org/x/tools/ast/astutil.
+func declImports(gen *ast.GenDecl, path string) bool {
+	if gen.Tok != token.IMPORT {
+		return false
+	}
+	for _, spec := range gen.Specs {
+		impspec := spec.(*ast.ImportSpec)
+		if importPath(impspec) == path {
+			return true
+		}
+	}
+	return false
+}
+
 func importPath(s ast.Spec) string {
 	t, err := strconv.Unquote(s.(*ast.ImportSpec).Path.Value)
 	if err == nil {