The contribution of livestock excreta to greenhouse gases (GHGs) emissions by sheep grazing in a typical steppe system in Guyuan county, Hebei province of the People's Republic of China was evaluated. Changes of methane (CH 4 ) and carbon dioxide (CO 2 ) fluxes from urine and dung patches excreted by sheep on grassland were measured for the first 144 h during July, August, September and October in 2011. CH 4 fluxes from dung patches significantly increased (P < 0.05) within the first 4–8 h, and CO 2 fluxes from urine patches significantly increased (P < 0.05) within the first 8 h. Urine patches cumulated the highest CO 2 emission (188.89 g m −2 ) in the first 144 h in August. Cumulative CH 4 emissions from urine patches and dung patches were −0.19 to 1.00 and −8.01 to 30.25 mg m −2 during the measurement period, and the control grassland was a net CH 4 sink (−14.66 to −0.29 mg m −2 ). Dung induced the highest CH 4 emission (23.46 μg g −2 ) in July. Significant positive correlations were found between soil temperature and GHGs fluxes (CH 4 in grassland: R 2 = 0.32, P < 0.01; CO 2 in urine patches: R 2 = 0.20, P < 0.05). Based on our measurement, the CH 4 emission produced by the daily excreta per adult sheep grazing in summer was estimated at 15.07 ± 4.90 mg.