The objective of the present study was to evaluate the efficacy and safety of sulphaquinoxaline administered in the drinking water on the control of coccidiosis in pigeons (Columba livia). Twenty naturally parasitized birds were divided in two groups of ten (treated and control). Parasitism was confirmed by observing oocysts through fecal exams (centrifugal flotation in saturated sucrose solution) on days -3, -2 and -1 before treatment. The employed formulation contained 25% sulphaquinoxaline (Avitrin Sulfa® Coveli) in a dilution of 10 drops/50mL of water, creating a final concentration of 0.26%. Birds were able to drink this solution per three consecutive days. Each bird was located in individual cages during the experimentation. Fecal examinations were performed 7 days post-treatment and thus, the birds were euthanized and necropsied. Segments of small intestines from all birds were collected, fixed in 10% formalin, and stained with hematoxylin-eosin. Histological examination was realized for observation of coccidian structures such as meronts and gametocytes. Birds were also evaluated for clinical parameters in a scale from 1 (normal) to 4 (highly affected): behavior, appetite, ocular mucosa, respiration, and presence of blood on feathers or feces. After treatment, all control birds remained positive for coccidian oocysts through fecal examination. While just one bird from the treated group remained positive. Sulphaquinoxaline demonstrated 90% efficacy in ceasing elimination of oocysts in pigeons when administered in a concentration of 0.26% in the drinking water. Histopathological examinations revealed that control birds presented various mucosal and submucosal coccidian evolutive stages. In contrast, only one out the treated group was found parasitized. No adverse symptoms were observed.