The comparative anticoccidial activity of sulfadimidine and methanolic extract of Thymus serpyllum was examined in rabbits experimentally infected with Eimeria infection in rabbits. This study was to demonstrate the effect of sulfadimidine and methanolic extract of Thymus serpyllum on faecal oocyst excreation and body weight change. The rabbits were divided into three groups each consisting of 6 animals. Group 1 served the as positive control (infected, non-treated), group 2 was the (infected and treated with extract), and rabbits in group 3 was (infected and treated with sulfadimidine). Each rabbit in the all groups was infected with single oral doses of 500.000 oocysts. Rabbits in group 2 and group 3 was treated with single oral doses of 100 mg/kg body weight of methanolic extract and single oral doses of 2 g/kg body weight of sulfadimidine. The overall faecal oocyst counts were ercorded for every consecutive day until day 36 of the study. Faecal oocyst counts were lower in group 2 and 3 than in group 1. Thymus serpyllum treated rabbits in group 2 had higher body weight gain over the day 24 post treatment period than in group 1 and 3. However body weight gain in group 2 was significantly (P<0.05) higher on day 8 only compared to group 1 and 3.