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Colorado Division of Wildlife currently considers the Texas horned lizard a species of special concern. From May 1995 to October 1997, Texas horned lizards were captured or collected during the active season from 6 counties in Colorado to document abundance and distribution of the species. We captured or collected 290 Texas horned lizards (170 alive and 120 dead on road). In Colorado, average snout-vent length (SVL) for adult males was not significantly different from females; the largest male and female lizards measured 84.9 mm SVL and 90.4 mm SVL, respectively. The sex ratio of adult males to adult females is 1M:1.4F. Results of distribution and habitat analysis indicated that the Texas horned lizard in Colorado is locally common in arid shortgrass and sand-sage prairie lacking ground litter. Activity of the Texas horned lizard in Colorado is diurnal in spring and fall and bimodal (almost crepuscular) in the summer. Texas horned lizards in Colorado apparently breed in May and June, and hatchlings emerge in late August to mid-September. Mortality due to vehicle traffic seems high, but because the Texas horned lizard occurs in remote areas, the Colorado population in general seems to be relatively stable.