diff --git a/command/agent/config.go b/command/agent/config.go
index 08d6db27f..03bce2593 100644
--- a/command/agent/config.go
+++ b/command/agent/config.go
@@ -175,14 +175,61 @@ func DefaultConfig() *Config {
 }
 
 // Merge merges two configurations.
-func (c *Config) Merge(c2 *Config) *Config {
-	result := new(Config)
+func (a *Config) Merge(b *Config) *Config {
+	var result Config = *a
 
-	result.Telemetry = c.Telemetry
-	if c2.Telemetry != nil {
-		result.Telemetry = c2.Telemetry
+	if b.Region != "" {
+		result.Region = b.Region
 	}
-	return result
+	if b.Datacenter != "" {
+		result.Datacenter = b.Datacenter
+	}
+	if b.NodeName != "" {
+		result.NodeName = b.NodeName
+	}
+	if b.DataDir != "" {
+		result.DataDir = b.DataDir
+	}
+	if b.LogLevel != "" {
+		result.LogLevel = b.LogLevel
+	}
+	if b.HttpAddr != "" {
+		result.HttpAddr = b.HttpAddr
+	}
+	if b.EnableDebug {
+		result.EnableDebug = true
+	}
+	// TODO: merge client config
+	if b.Client != nil {
+		result.Client = b.Client
+	}
+	// TODO: merge server config
+	if b.Server != nil {
+		result.Server = b.Server
+	}
+	// TODO: merge telemetry config
+	if b.Telemetry != nil {
+		result.Telemetry = b.Telemetry
+	}
+	if b.LeaveOnInt {
+		result.LeaveOnInt = true
+	}
+	if b.LeaveOnTerm {
+		result.LeaveOnTerm = true
+	}
+	if b.EnableSyslog {
+		result.EnableSyslog = true
+	}
+	if b.SyslogFacility != "" {
+		result.SyslogFacility = b.SyslogFacility
+	}
+	if b.DisableUpdateCheck {
+		result.DisableUpdateCheck = true
+	}
+	if b.DisableAnonymousSignature {
+		result.DisableAnonymousSignature = true
+	}
+	return &result
 }
 
 // LoadConfig loads the configuration at the given path, regardless if
diff --git a/command/agent/config_test.go b/command/agent/config_test.go
new file mode 100644
index 000000000..f58abcf4f
--- /dev/null
+++ b/command/agent/config_test.go
@@ -0,0 +1,45 @@
+package agent
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestConfig_Merge(t *testing.T) {
+	c1 := &Config{
+		Region:                    "region1",
+		Datacenter:                "dc1",
+		NodeName:                  "node1",
+		DataDir:                   "/tmp/dir1",
+		LogLevel:                  "INFO",
+		HttpAddr:                  "127.0.0.1:4646",
+		EnableDebug:               false,
+		LeaveOnInt:                false,
+		LeaveOnTerm:               false,
+		EnableSyslog:              false,
+		SyslogFacility:            "local0.info",
+		DisableUpdateCheck:        false,
+		DisableAnonymousSignature: false,
+	}
+
+	c2 := &Config{
+		Region:                    "region2",
+		Datacenter:                "dc2",
+		NodeName:                  "node2",
+		DataDir:                   "/tmp/dir2",
+		LogLevel:                  "DEBUG",
+		HttpAddr:                  "0.0.0.0:80",
+		EnableDebug:               true,
+		LeaveOnInt:                true,
+		LeaveOnTerm:               true,
+		EnableSyslog:              true,
+		SyslogFacility:            "local0.debug",
+		DisableUpdateCheck:        true,
+		DisableAnonymousSignature: true,
+	}
+
+	result := c1.Merge(c2)
+	if !reflect.DeepEqual(result, c2) {
+		t.Fatalf("bad: %#v", result)
+	}
+}