Members of Ammocrypta (Percidae), known as sand darters, have experienced widespread population declines, yet little is known regarding their ecology and life history. The purpose of this study was to examine life history traits and provide much needed information on the western sand darter (Ammocrypta clara) from a population in Northeast Arkansas. The Strawberry, Black, and Current rivers were sampled by seine or trawl from Jun. 2007–Sep. 2008. Life history traits were examined on 379 specimens. Mean size was 42.9 mm standard length (max. 50 km SL) and males and females reached maturity between 35–40 mm SL. The spawning season was May to Aug. and mean monthly gonadosomatic index (GSI) ranged from 3.4–4.9%. Gravid females averaged 57 eggs per clutch and mean egg size was 0.79 mm across mature, ripening, and ripe stages. Significant relationships existed between female standard length, ovarian mass, and clutch size. Observation of captive specimens in aquaria revealed crepuscular spawning with eggs (mean  =  1.22 mm) buried singly in the sand and clutches released over short periods of time (hours to days). Overall, A. clara from Arkansas possessed several life history traits that differed from data reported for A. clara in Wisconsin and other species of Ammocrypta. We found that fish were smaller in size, had lower GSI values, smaller clutch sizes, and smaller egg sizes compared to other Ammocrypta, reflecting potentially important life history trade-offs between size and age (longevity) and the relationship among GSI, clutch size, and egg size.