Populations of lesser prairie-chickens (Tympanuchus pallidicinctus) have declined sharply across the range of the species, including southeastern New Mexico. Several possible causes for this decline have been suggested, including overgrazing by livestock. To test this hypothesis, vegetative composition of active and abandoned leks of lesser prairie-chickens and the pastures in which they were located was measured using the line-point sampling method. Vegetative composition of active leks and the pastures in which they were located was significantly different from those of abandoned leks and surrounding pastures in all 3 years of the study. Active leks and surrounding pastures had significantly more bluestem (Andropogon) and less dropseed (Sporobolus) than did abandoned leks and surrounding pastures. Abandoned leks were closer to honey mesquites (Prosopis glandulosa) >60 cm in height than were active leks. Results are symptomatic of overgrazing, which is detrimental to populations of lesser prairie-chickens.