Because prey acquisition in young organisms often has profound effects later in life, understanding the foraging ecology of early age classes is important. We examined diet and prey preference of neonate Eastern Massasaugas (Sistrurus c. catenatus) at Carlyle Lake, Clinton County, Illinois. Prey recovered from free-ranging neonates consisted primarily of southern short-tailed shrews (Blarina carolinensis). In feeding trials, neonates demonstrated a preference for snake prey, disinterest in anuran and insect prey and indifference toward mammal prey. Because of gape limitations, neonates may have difficulty ingesting small mammals, but snakes are comparably easier to ingest and are the most common prey item of young S. c. catenatus in other parts of their range. Blarina carolinensis has not been reported previously from the diet of S. c. catenatus as their ranges overlap only in southwestern Illinois. Blarina carolinensis is considerably smaller than most mammals preyed upon by older age classes and would be easier for neonates to ingest. Thus, at Carlyle Lake, snakes may not be as important a prey resource for neonate massasaugas as in other parts of their range due to the availability of B. carolinensis.