Call IsDefined with string containing member name.
<Flags> Public Enum PetType As Integer None = 0 Dog = 1 Cat = 2 Rodent = 4 Bird = 8 Reptile = 16 Other = 32 End Enum Module Example Public Sub Main() Dim value As Object value = "Rodent" Console.WriteLine("{0}: {1}", value, [Enum].IsDefined(GetType(PetType), value)) End Sub End Module