diff --git a/cmd/helm/repo_add.go b/cmd/helm/repo_add.go
index 15d4c842e..8ae78f473 100644
--- a/cmd/helm/repo_add.go
+++ b/cmd/helm/repo_add.go
@@ -17,16 +17,20 @@ limitations under the License.
 package main
 
 import (
+	"context"
 	"fmt"
 	"io"
+	"syscall"
+	"time"
+
+	"golang.org/x/crypto/ssh/terminal"
 
+	"github.com/gofrs/flock"
 	"github.com/spf13/cobra"
 
-	"golang.org/x/crypto/ssh/terminal"
 	"k8s.io/helm/pkg/getter"
 	"k8s.io/helm/pkg/helm/helmpath"
 	"k8s.io/helm/pkg/repo"
-	"syscall"
 )
 
 type repoAddCmd struct {
@@ -131,6 +135,25 @@ func addRepository(name, url, username, password string, home helmpath.Home, cer
 		return fmt.Errorf("Looks like %q is not a valid chart repository or cannot be reached: %s", url, err.Error())
 	}
 
+	// Lock the repository file for concurrent goroutines or processes synchronization
+	fileLock := flock.New(home.RepositoryFile())
+	lockCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	locked, err := fileLock.TryLockContext(lockCtx, time.Second)
+	if err == nil && locked {
+		defer fileLock.Unlock()
+	}
+	if err != nil {
+		return err
+	}
+
+	// Re-read the repositories file before updating it as its content may have been changed
+	// by a concurrent execution after the first read and before being locked
+	f, err = repo.LoadRepositoriesFile(home.RepositoryFile())
+	if err != nil {
+		return err
+	}
+
 	f.Update(&c)
 
 	return f.WriteFile(home.RepositoryFile(), 0644)
diff --git a/cmd/helm/repo_add_test.go b/cmd/helm/repo_add_test.go
index 5a458cef7..7443a476a 100644
--- a/cmd/helm/repo_add_test.go
+++ b/cmd/helm/repo_add_test.go
@@ -17,13 +17,18 @@ limitations under the License.
 package main
 
 import (
+	"fmt"
 	"io"
 	"os"
+	"os/exec"
+	"strings"
+	"sync"
 	"testing"
 
 	"github.com/spf13/cobra"
 
 	"k8s.io/helm/pkg/helm"
+	"k8s.io/helm/pkg/helm/helmpath"
 	"k8s.io/helm/pkg/repo"
 	"k8s.io/helm/pkg/repo/repotest"
 )
@@ -101,3 +106,111 @@ func TestRepoAdd(t *testing.T) {
 		t.Errorf("Duplicate repository name was added")
 	}
 }
+func TestRepoAddConcurrentGoRoutines(t *testing.T) {
+	ts, thome, err := repotest.NewTempServer("testdata/testserver/*.*")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cleanup := resetEnv()
+	defer func() {
+		ts.Stop()
+		os.RemoveAll(thome.String())
+		cleanup()
+	}()
+
+	settings.Home = thome
+	if err := ensureTestHome(settings.Home, t); err != nil {
+		t.Fatal(err)
+	}
+
+	var wg sync.WaitGroup
+	wg.Add(3)
+	for i := 0; i < 3; i++ {
+		go func(name string) {
+			defer wg.Done()
+			if err := addRepository(name, ts.URL(), "", "", settings.Home, "", "", "", true); err != nil {
+				t.Error(err)
+			}
+		}(fmt.Sprintf("%s-%d", testName, i))
+	}
+	wg.Wait()
+
+	f, err := repo.LoadRepositoriesFile(settings.Home.RepositoryFile())
+	if err != nil {
+		t.Error(err)
+	}
+
+	var name string
+	for i := 0; i < 3; i++ {
+		name = fmt.Sprintf("%s-%d", testName, i)
+		if !f.Has(name) {
+			t.Errorf("%s was not successfully inserted into %s", name, settings.Home.RepositoryFile())
+		}
+	}
+}
+
+// Same as TestRepoAddConcurrentGoRoutines but with repository additions in sub-processes
+func TestRepoAddConcurrentSubProcesses(t *testing.T) {
+	goWantHelperProcess := os.Getenv("GO_WANT_HELPER_PROCESS")
+	if goWantHelperProcess == "" {
+		// parent
+
+		ts, thome, err := repotest.NewTempServer("testdata/testserver/*.*")
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		settings.Home = thome
+
+		cleanup := resetEnv()
+		defer func() {
+			ts.Stop()
+			os.RemoveAll(thome.String())
+			cleanup()
+		}()
+		if err := ensureTestHome(settings.Home, t); err != nil {
+			t.Fatal(err)
+		}
+
+		var wg sync.WaitGroup
+		wg.Add(2)
+		for i := 0; i < 2; i++ {
+			go func(name string) {
+				defer wg.Done()
+
+				cmd := exec.Command(os.Args[0], "-test.run=^TestRepoAddConcurrentSubProcesses$")
+				cmd.Env = append(os.Environ(), fmt.Sprintf("GO_WANT_HELPER_PROCESS=%s,%s", name, ts.URL()), fmt.Sprintf("HELM_HOME=%s", settings.Home))
+				out, err := cmd.CombinedOutput()
+				if len(out) > 0 || err != nil {
+					t.Fatalf("child process: %q, %v", out, err)
+				}
+			}(fmt.Sprintf("%s-%d", testName, i))
+		}
+		wg.Wait()
+
+		f, err := repo.LoadRepositoriesFile(settings.Home.RepositoryFile())
+		if err != nil {
+			t.Error(err)
+		}
+
+		var name string
+		for i := 0; i < 2; i++ {
+			name = fmt.Sprintf("%s-%d", testName, i)
+			if !f.Has(name) {
+				t.Errorf("%s was not successfully inserted into %s", name, settings.Home.RepositoryFile())
+			}
+		}
+	} else {
+		// child
+		s := strings.Split(goWantHelperProcess, ",")
+		settings.Home = helmpath.Home(os.Getenv("HELM_HOME"))
+		repoName := s[0]
+		tsURL := s[1]
+		if err := addRepository(repoName, tsURL, "", "", settings.Home, "", "", "", true); err != nil {
+			t.Fatal(err)
+		}
+
+		os.Exit(0)
+	}
+}
diff --git a/glide.lock b/glide.lock
index b736eec9a..a9d12597c 100644
--- a/glide.lock
+++ b/glide.lock
@@ -114,6 +114,8 @@ imports:
   - syntax/lexer
   - util/runes
   - util/strings
+- name: github.com/gofrs/flock
+  version: 392e7fae8f1b0bdbd67dad7237d23f618feb6dbb
 - name: github.com/gogo/protobuf
   version: 342cbe0a04158f6dcb03ca0079991a51a4248c02
   subpackages:
diff --git a/glide.yaml b/glide.yaml
index ef2d27cf5..49e9eec4d 100644
--- a/glide.yaml
+++ b/glide.yaml
@@ -67,6 +67,8 @@ import:
   - package: github.com/jmoiron/sqlx
     version: ^1.2.0
   - package: github.com/rubenv/sql-migrate
+  - package: github.com/gofrs/flock
+    version: v0.7.1
 
 testImports:
   - package: github.com/stretchr/testify