Deciduous premolars of Mammut americanum have received relatively little study, and previous work was based on small sample sizes. We present morphologic descriptions and quantitative data for a sample of over 135 deciduous premolars of M. americanum from Florida. Most second and third deciduous premolars are bilophodont, although a few anomalous teeth deviate from this pattern to a varying degree. Although the premolars are morphologically similar to the adult molars in many respects, differences in development of cingula, orientation of lophs and lophids, and relative strengths of enamel crests are observed. Distal cingula and stylar cusps are the most variable portions of the crown. Crown length increases distally along the tooth row, with no observed overlap in length between adjacent teeth.