We analyze the inclusiveness and effectiveness of agricultural cooperatives in Rwanda. We estimate mean income and poverty effects of cooperative membership using propensity score matching techniques. We analyze heterogeneous treatment effects across farmers by analyzing how estimated treatment effects vary over farm and farmer characteristics and over the estimated propensity score. We find that cooperative membership in general increases income and reduces poverty and that these effects are largest for larger farms and in more remote areas. We find evidence of a negative selection as impact is largest for farmers with the lowest propensity to be a cooperative member.