Scattering of an acoustic wave from a thin rough circular disk is studied using an integral equation method. The T matrix (transition matrix), which governs the relation between the incident and scattered fields, is determined using an integral representation of the Helmholtz equation. The rough surface is modeled by a superposition of a number of sinusoidal surfaces that are randomly translated and rotated with respect to each other. Some numerical results for the scattered field are presented in the case of an incident plane wave. One conclusion is that the amplitude of the backscattered field is not only dependent on parameters like frequency, angle of incidence, and overall characteristics of the surface like rms height and correlation function. The exact geometry of the rough object is also vitally important for its scattering properties, which implies that a statistical approach to the problem is of limited value.