This paper deals with the doctrine of transubstantial change advocated by Mulla Sadra in which substances as well as accidents are thought to be in constant and gradual change. Against Aristotle’s doctrine of accidental change, Mulla Sadra argues that no stable ground can bring about change and since substance is renewable it cannot carry identity of a changing existent. Here we investigate whether identity is possible or not. If it is possible then what becomes a ground for establishing identity of changing substances.