Little is known about the ecology and behavior of Rock Rattlesnakes (Crotalus lepidus) despite the species' wide geographic distribution throughout the southwestern United States and central Mexico. The goal of this study was to quantify space use, movement patterns, and habitat use by C. lepidus in the Chihuahuan Desert of extreme west Texas. We used radiotelemetry to monitor subjects during at least one activity season from 2007 to 2010. Mean (±1 SE) home range size for all individuals was 13.69 ± 3.06 ha, and mean daily movement rate was 8.46 ± 1.45 m/d. Although monthly movement rates were similar, movement was greatest in September, corresponding with the peak of the mating season for C. lepidus at our study site. We used multinomial logit models to analyze habitat use patterns among telemetered snakes while controlling for subject, estimated habitat availability, and season. Our subjects were most often observed using small arroyos, despite these habitats being relatively limited spatially within snake home ranges. Conversely, habitats typically associated with C. lepidus life-history (e.g., alluvial rocky slopes) were more available to our subjects, but were used less frequently overall. We also detected seasonal associations in habitat use, with subjects being more likely to use alluvial rocky slopes during spring and shifting to arroyo habitat throughout summer. Snakes also used microhabitats nonrandomly, most often seeking refuge under shrubs where ground cover consisted primarily of vegetation rather than rock or gravel. Our study presents a detailed analysis of habitat and microhabitat use by this species, and the patterns of movement and home range size reported here largely contrast to those found in the available literature on the spatial ecology of C. lepidus.