In this study, investigation was done to determine the optimum combination of cow dung (CD) and horse dung (HD) for enhanced biogas production and plant stability. Anaerobic co-digestion of CD and HD at varying percentage combination was carried out in five (5) identical 25 L cylindrical digesters (A-E) for a retention period of 37 days, at an average ambient temperature of 33 °C. Using the Microsoft excel solver function, 2010 version,