diff --git a/README.md b/README.md
index 848d92d..bcccd67 100644
--- a/README.md
+++ b/README.md
@@ -246,6 +246,11 @@ serverCmd.Flags().Int("port", 1138, "Port to run Application server on")
 viper.BindPFlag("port", serverCmd.Flags().Lookup("port"))
 ```
 
+The above example would also work with
+[Cobra's Persistent Flags](https://github.com/spf13/cobra#persistent-flags),
+but careful not to mix and match Cobra `Flags` and `PersistentFlags` when
+binding with Viper.
+
 You can also bind an existing set of pflags (pflag.FlagSet):
 
 Example:
diff --git a/viper.go b/viper.go
index 963861a..9b980e0 100644
--- a/viper.go
+++ b/viper.go
@@ -799,9 +799,15 @@ func (v *Viper) BindPFlags(flags *pflag.FlagSet) error {
 //	 serverCmd.Flags().Int("port", 1138, "Port to run Application server on")
 //	 Viper.BindPFlag("port", serverCmd.Flags().Lookup("port"))
 //
+// NOTE: Be consistent with either Cobra's Flags() or PersistentFlags(),
+//       do not mix them.
 func BindPFlag(key string, flag *pflag.Flag) error { return v.BindPFlag(key, flag) }
 func (v *Viper) BindPFlag(key string, flag *pflag.Flag) error {
-	return v.BindFlagValue(key, pflagValue{flag})
+	var flagVal FlagValue
+	if flag != nil {
+		flagVal = pflagValue{flag}
+	}
+	return v.BindFlagValue(key, flagVal)
 }
 
 // BindFlagValues binds a full FlagValue set to the configuration, using each flag's long
diff --git a/viper_test.go b/viper_test.go
index 774ca11..e1f850a 100644
--- a/viper_test.go
+++ b/viper_test.go
@@ -597,6 +597,15 @@ func TestBindPFlag(t *testing.T) {
 
 }
 
+func TestBindPFlagToNil(t *testing.T) {
+	v := New()
+	// nil arg often comes as an accident from calling something like:
+	//     `myCobraCmd.Flags().Lookup("missingFlag")`
+	err := v.BindPFlag("host", nil)
+	assert.Equal(t, nil, v.Get("host")) // `Get` here used to panic
+	assert.EqualError(t, err, `flag for "host" is nil`)
+}
+
 func TestBoundCaseSensitivity(t *testing.T) {
 	assert.Equal(t, "brown", Get("eyes"))