In this article, results obtained from an experimental investigation conducted to determine the wave-induced geometric characteristics of offshore ripples and bars are presented. The experiments were performed using irregular waves. Natural beach sand was used in the study, where the mean diameter was 0.35 mm and the specific gravity was 2.63. The initial slope of the beach was 1:5. Different wave groups were generated over the initially flat beach, and a number of characteristics were determined. These include the ripple number, individual and average ripple heights,, individual and average ripple lengths and the length of the offshore bar. The results of the experimental study were evaluated and empirical expressions based on the results were formulated. (C) 2002 Elsevier Science Ltd. All rights reserved.