The oviposition choice of Callosobruchus maculatus was tested by providing different ratios of azuki and mung beans to the female. The results show that females preferred to deposit eggs on azuki beans. The fraction of eggs laid on azuki beans increased with increasing ratio of azuki beans, whereas it decreased with a decreasing duration of oviposition. Even when the data were transformed to a preference index, the effects of host ratio and oviposition duration were not eliminated. The ovipositional behavior was observed on different beans. The results indicate that the probability of the female encountering azuki beans was significantly higher than that of mung beans, but even when the female was provided with the same probability of evcounter it still preferred to lay eggs on azuki beans. Females tended to spent more inspecting time on azuki beans than on mung beans, but the handling time spent on these two hosts was found no differences. The results indicate that the relationship between egg-laying behavior and oviposition preference may provide important information for the evaluation of host preference of cowpea weevils.