The gonadal cycle of Tegula eiseni (Jordan, 1936) was determined on monthly samples (25–30 organisms) collected from a population in Bahía Asunción, B.C.S., from January 2006 to December 2006. The results of the histological study indicate that both males and females show stages of gametogenesis and gonad maturation throughout the year and only two major spawning events: one in spring and another in fall. The species behaved as a partial spawner, and only at certain times was total spawning observed in females. Maturation and release or spawning times seem to be closely related to seasonal temperature rises and abrupt changes in surface sea water temperature, which occur at brief intervals for several days at certain times of year.