Dual-purpose cowpea (DPC) and dual-purpose groundnut (DPG) varieties provide good yields, improved soil fertility through nitrogen fixation, and, at the same time, provide large amounts of good quality fodder to be used as feed or manure in crop-livestock integrated farming systems in Ghana. Hence, these varieties play a significant role in improving the productivity and efficiency of crop-livestock systems in Ghana. This paper estimates the population potential adoption rates of the DPC and DPG varieties and their determinants among integrated crop-livestock farmers in Ghana when there is full access to complete and accurate information and access to the seed by farmers. Because these varieties have been newly introduced, not all farmers are aware of them nor have access to the seed. Using cross-sectional data from 608 farmers, this paper applies the average-treatment-effect method to estimate the population potential adoption rates of the DPC and DPG varieties and coefficients of their determinants among integrated crop-livestock farmers. The result shows that, potential population adoption rates of DPC and DPG could reach 78% and 85%, if all farmers have knowledge about the varieties, and up to 83% and 94%, respectively, if all the farmers have knowledge and access to seed. These results indicate that there are adoption gaps of 42% and 47% due to incomplete knowledge of DPC and DPG and 47% and 55% due to incomplete access to seed of the respective varieties. The adoption gaps suggest that there is still potential for increasing the adoption rates of these dual purpose legumes among crop-livestock farmers in Ghana if exposure and access to seed of the varieties are universal among the farmers. Also farmers with access to extension, research institutes and credit are more likely to be exposed, have access to the seed and adopt the varieties.