Three experiments were conducted to provide a quantitative description of copulation in Mongolian gerbils (Meriones unguiculatus). The overall copulatory pattern of gerbils may be characterized as containing multiple intromissions, multiple ejaculations, no intravaginal thrusting, and no lock. Mean intromission frequencies failed to approach the exceptionally high values reported by previous workers. As the present data indicate that gerbils lie within rather than outside the range of performance of other muroid rodents, it is suggested that earlier hypotheses regarding unusual insensitivity of gerbil reproductive systems are unnecessary. Sexual satiety (30 min with no intromissions) was attained following a mean of 4.8–6.9 ejaculations. In contrast to most other species, males typically failed to complete the final ejaculatory series, even after many intromissions. Implications of this unusual mode of development of satiety are discussed.