The prevalence and distribution of “brainworm” (Parelaphostrongylus tenuis) were examined in northern New York (USA) from 1986 to 1989. Sixty nine (46%) of 151 white-tailed deer (Odocoileus virginianus) heads examined, contained adult P. tenuis. The proportion of infected individuals was not significantly different between males and females. Prevalence was significantly greater in the adult age class as compared to the juvenile age class (P < 0.01). Deer pellet samples were examined for prevalence of P. tenuis-like larvae. Pellet samples in New York had an overall prevalence of 60%. The effects of precipitation and host density on prevalence of P. tenuis in deer was not significant.