Thin polymer films occupy an eminent position in modern science and technology both in and of themselves and as models for bulk polymer systems. Much of their function depends on their interaction with external (often hostile) environments. Thus, methods for obtaining information about the chemistry of these films as a function of depth are a critical need. This review critically evaluates the methods which have been applied up to this point for depth profiling in polymers and concentrates on two methods: optical depth profiling using excitation in a slab waveguide, and nuclear reaction profiling. Guided wave experiments have been useful in situations in which the species being determined forms only a minor or trace constitutent of the thin film matrix, while nuclear reaction profiling has been applied primarily to profiles of protonated and deuterated polymers in studies of interdiffusion. Other techniques for depth profiling have more limited applications.