The calcium-binding protein parvalbumin (PV) was localized in the basolateral amygdala of the rat, cat, dog and monkey using immunohistochemical techniques. In all species, neuronal cell bodies and fibers that are immunoreactive to PV were observed in the basolateral amygdala. In most of the amygdala, PV-immunoreactive cells had the appearance of aspiny local circuit neurons. Based primarily on the shape of the soma, PV-immunoreactive aspiny neurons were divided into three main types. Type 1 cells had a spherical soma and more than 3 dendrites, type 2 cells had angular and multipolar somata of variable sizes, and type 3 cells had fusiform somata and dendrites emanated from the opposite poles of somata. PV-immunoreactive varicose fibers formed basket-like plexi around unstained neurons, which suggests that PV is located in GABAergic basket cells, respectively. PV-immunoreactivities in the mammalian basolateral amygdala were morphologically similar, rather than different in all species.