Abstract: Internal parasitism of feedlot cattle has been documented to reduce performance and impair immune function. GI nematodes are chronic pervasive infections that contribute worldwide to morbidity and mortality in humans and in livestock. The objective of this study was to evaluation of Kepromec pour-on effect on decreasing of gastrointestinal nematodes. In this study, 60 male and female hybrid cows were allocated into two 30 individual groups. Then, Kepromec pour-on was administrated at the dose of 1 mg 20 kg-1. Results showed that Kepromec pour-on has about 90% efficacy on GI nematodes. Thus, use of Kepromec to prohibition of GI nematodes is recommended.