We estimated species richness, distribution, and relative abundance of herpetofauna across a 1,800-m elevation gradient in the Rincon Mountains and compared patterns of occurrence of species with other mountain ranges in southeastern Arizona. We detected 2,378 individuals of 40 species during 596 h of visual-encounter surveys, and 1,793 individuals including six additional species incidentally during 2001 and 2002. Based on probabilistic methods, we estimate that as many as 57 species likely are present in the Rincon Mountains; past observations and expert opinion also suggest as many as 57 species likely are present. Species richness declined with increasing elevation. Relative abundance declined with increasing elevation for seven species, increased with elevation for three species, and was greatest at middle elevations for three species. The Rincon Mountains lack some species that occur in nearby mountain ranges of similar size and elevation, possibly due to climatic or historical factors. Our study was the first detailed inventory of herpetofauna in the Rincon Mountains at a time when these communities may be undergoing significant change.