To improve climate change mitigation and environmental sustainability in Nigeria, agricultural co-operative societies should make effective use of indigenous agricultural and environmental conservation practices. However, indigenous knowledge and the institutional role of agricultural co-operative societies continue to be insufficiently integrated and efforts to mitigate climate change still heavily rely on contemporary technologies. The study therefore examined how using indigenous agricultural practices by co-operative societies affects climate change mitigation, as well as how using indigenous environmental conservation practices by agricultural co-operative societies affects climate change mitigation. Descriptive survey research design was adopted for the study, with 384 farmers from the three agricultural zones of Enugu State sampled through multistage sampling. Data were collected using a well-structured and validated questionnaire with a reliability coefficient of 0.83 obtained through Cronbach’s Alpha. SPSS 28 was used to descriptively analyze data in mean based on a 4-point scale. Results showed that the utilization of indigenous agricultural practices (x̄ =2.792) and utilization of indigenous environmental conservation practices (x̄ =2.783) by agricultural co-operative societies significantly affect climate change mitigation in Nigeria. Through programs for training indigenous knowledge, the government should support agricultural co-operatives and increase community involvement in climate mitigation initiatives. Through ongoing member education and co-operative environmental initiatives across the country, agricultural co-operative societies should institutionalize indigenous conservation practices. By illustrating how agricultural co-operative societies institutionalize indigenous agricultural and environmental conservation practices as complementary mechanisms for bolstering climate change mitigation in Nigeria, the study closed the empirical gap.