A quantitative assessment of impact by pocket gophers (Thomomys talpoides) on vegetative production of rangeland in southwestern Alberta, Canada, was obtained. The technique described outlines a method of experimental plot selection, design, treatment, and evaluation over a three-month period, which is relatively simple and has potential for application in other types of rodent damage assessments. The experimental design is particularly useful in that it allows the researcher to correlate the presence of rodents to measurable changes in net vegetation production. In this study, forage production increased 16 percent during the final 60 days of the three-month study on plots where pocket gophers were removed completely. Plots treated with a machine application of rodenticide showed a four and five percent increase in forage production, respectively. During the same period, forage yields on untreated control plots (where pocket gophers were not removed) declined 18 percent (p < 0.001).