So I am working with WCF and my services return types that contain generic lists. WCF is currently converting these to arrays over the wire. Is there a way I configure WCF to convert them back to lists afterwards? I know there is a way by clicking advanced when you add a service reference but I am looking for a solution in configuration files or something similar. [DataContract(IsReference = true)] public class SampleObject { [DataMember] public long ID { get; private set; } [DataMember] public ICollection<AnotherObject> Objects { get; set; } } It is very odd, also, because one service returns it as a list and the other as an array and I am pretty sure they are configured identically.