A variety of bioactive compounds isolated from various botanical sources have been found to have therapeutic and immunotherapeutic effects on chicken coccidiosis. This study aimed to evaluate the anti-coccidial potential of Enteromorpha prolifera polysaccharide (EP) in indigenous chickens in Northwest Ethiopia. A total of 78 male indigenous chickens were used for this study. The study had two treatment groups: (1) the EP non-supplemented group (those fed on diets without EP and Eimeria oocyst inoculated) and (2) the EP group (those receiving diets supplemented with 400mgEP/kg diet and Eimeria oocyst inoculated). Each treatment group had five replications. Following fourteen days of EP supplementation, 1.5×104 oocysts of mixed Eimeria species were inoculated into individual birds. EP-supplemented chicken showed significantly lower (p<0.05) oocyst counts compared to non-supplemented ones on 9 and 11 days post-challenge. In addition, chickens in the EP-supplemented group showed less severe lesion scores, with an average score of 1.33. Chickens that received EP showed a maximum of 27.27% protection against lesions. In contrast, the non-supplemented chickens had a lower percentage of protection (19.83%). The maximum anti-coccidial index value (146.98) was obtained from EP-supplemented chickens. Chickens in the EP-supplemented group exhibited a significantly higher (p<0.05) weight gain. Overall, the inclusion of EP in chickens' diets shows promise as a potential anti-coccidial strategy. However, additional research is required to explore the mechanisms by which EP in chickens' diet could involve in increasing the protection ability of chickens against coccidiosis.