A simple empirical model is proposed to retrieve wave period from Ku-band radar altimeter backscatter and significant wave height. The model formulation is heuristic, and fitted using a large dataset of collocated Topex altimeter and buoys measurements. Empirical models are proposed for the zero up-crossing, the mean and the peak wave period, and compared with models by Davies et al. <1997> and Hwang et al. <1998>. Their performance is assessed using an independent validation dataset, and gives a retrieval error of 0.8s. Regional analysis indicates that the wave period models perform better in wind seas than in swell-dominated conditions.