diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7a2f6337f..1edb00e63 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,10 @@ BUG FIXES:
 
 * core: More plugin server fixes that avoid hangs on OS X 10.7 [GH-87]
 * virtualbox: More robust version parsing for uploading guest additions. [GH-69]
+* virtualbox: Output dir and VM name defaults depend on build name,
+  avoiding collisions. [GH-91]
+* vmware: Output dir and VM name defaults depend on build name,
+  avoiding collisions. [GH-91]
 
 ## 0.1.2 (June 29, 2013)
 
diff --git a/builder/virtualbox/builder.go b/builder/virtualbox/builder.go
index 8b6fc0ab3..5d1f9bcce 100644
--- a/builder/virtualbox/builder.go
+++ b/builder/virtualbox/builder.go
@@ -48,7 +48,8 @@ type config struct {
 	VBoxManage         [][]string    `mapstructure:"vboxmanage"`
 	VMName             string        `mapstructure:"vm_name"`
 
-	PackerDebug bool `mapstructure:"packer_debug"`
+	PackerBuildName string `mapstructure:"packer_build_name"`
+	PackerDebug     bool   `mapstructure:"packer_debug"`
 
 	RawBootWait        string `mapstructure:"boot_wait"`
 	RawShutdownTimeout string `mapstructure:"shutdown_timeout"`
@@ -86,7 +87,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 	}
 
 	if b.config.OutputDir == "" {
-		b.config.OutputDir = "virtualbox"
+		b.config.OutputDir = fmt.Sprintf("output-%s", b.config.PackerBuildName)
 	}
 
 	if b.config.RawBootWait == "" {
@@ -114,7 +115,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 	}
 
 	if b.config.VMName == "" {
-		b.config.VMName = "packer"
+		b.config.VMName = fmt.Sprintf("packer-%s", b.config.PackerBuildName)
 	}
 
 	errs := make([]error, 0)
diff --git a/builder/virtualbox/builder_test.go b/builder/virtualbox/builder_test.go
index f8902a44d..eb080af47 100644
--- a/builder/virtualbox/builder_test.go
+++ b/builder/virtualbox/builder_test.go
@@ -13,6 +13,8 @@ func testConfig() map[string]interface{} {
 		"iso_md5":      "foo",
 		"iso_url":      "http://www.google.com/",
 		"ssh_username": "foo",
+
+		packer.BuildNameConfigKey: "foo",
 	}
 }
 
@@ -36,7 +38,7 @@ func TestBuilderPrepare_Defaults(t *testing.T) {
 		t.Errorf("bad guest OS type: %s", b.config.GuestOSType)
 	}
 
-	if b.config.OutputDir != "virtualbox" {
+	if b.config.OutputDir != "output-foo" {
 		t.Errorf("bad output dir: %s", b.config.OutputDir)
 	}
 
@@ -52,7 +54,7 @@ func TestBuilderPrepare_Defaults(t *testing.T) {
 		t.Errorf("bad ssh port: %d", b.config.SSHPort)
 	}
 
-	if b.config.VMName != "packer" {
+	if b.config.VMName != "packer-foo" {
 		t.Errorf("bad vm name: %s", b.config.VMName)
 	}
 }
diff --git a/builder/vmware/builder.go b/builder/vmware/builder.go
index 5a0e2159d..d8a8f27b6 100644
--- a/builder/vmware/builder.go
+++ b/builder/vmware/builder.go
@@ -50,7 +50,8 @@ type config struct {
 	VNCPortMin        uint              `mapstructure:"vnc_port_min"`
 	VNCPortMax        uint              `mapstructure:"vnc_port_max"`
 
-	PackerDebug bool `mapstructure:"packer_debug"`
+	PackerBuildName string `mapstructure:"packer_build_name"`
+	PackerDebug     bool   `mapstructure:"packer_debug"`
 
 	RawBootWait        string `mapstructure:"boot_wait"`
 	RawShutdownTimeout string `mapstructure:"shutdown_timeout"`
@@ -78,7 +79,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 	}
 
 	if b.config.VMName == "" {
-		b.config.VMName = "packer"
+		b.config.VMName = fmt.Sprintf("packer-%s", b.config.PackerBuildName)
 	}
 
 	if b.config.HTTPPortMin == 0 {
@@ -102,7 +103,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 	}
 
 	if b.config.OutputDir == "" {
-		b.config.OutputDir = "vmware"
+		b.config.OutputDir = fmt.Sprintf("output-%s", b.config.PackerBuildName)
 	}
 
 	if b.config.SSHPort == 0 {
diff --git a/builder/vmware/builder_test.go b/builder/vmware/builder_test.go
index bc8e8a801..8d32636d8 100644
--- a/builder/vmware/builder_test.go
+++ b/builder/vmware/builder_test.go
@@ -13,6 +13,8 @@ func testConfig() map[string]interface{} {
 		"iso_md5":      "foo",
 		"iso_url":      "http://www.packer.io",
 		"ssh_username": "foo",
+
+		packer.BuildNameConfigKey: "foo",
 	}
 }
 
@@ -66,7 +68,7 @@ func TestBuilderPrepare_Defaults(t *testing.T) {
 		t.Errorf("bad disk name: %s", b.config.DiskName)
 	}
 
-	if b.config.OutputDir != "vmware" {
+	if b.config.OutputDir != "output-foo" {
 		t.Errorf("bad output dir: %s", b.config.OutputDir)
 	}
 
@@ -74,7 +76,7 @@ func TestBuilderPrepare_Defaults(t *testing.T) {
 		t.Errorf("bad wait timeout: %s", b.config.SSHWaitTimeout)
 	}
 
-	if b.config.VMName != "packer" {
+	if b.config.VMName != "packer-foo" {
 		t.Errorf("bad vm name: %s", b.config.VMName)
 	}
 }