The aim of the current study was to assess the adaptability and stability of iron and zinc concentrations and grain yield in cowpea lines to release new cultivars. Forty-four genotypes were distributed in two experiments, climbing and upright lines, with different population densities. They were assessed in four rainfed and three irrigated environments in two randomized block designs with three repetitions. Significant statistical differences were observed (p< 0.01) in the treatment, environment, and treatment × environment interaction mean squares for all variables. The lines that showed the highest iron and zinc concentrations also showed grain yields below the overall mean in both experiments. The three applied methods showed similar results in the selection of superior materials. C4I and T16_2R in the climbing experiment and C2J in the upright experiment showed grain yield equal to or greater than the overall experiment means of 1034 and 1130 kg ha−1, respectively, with iron and zinc means concentrations 15% greater than the control cultivars, as well as wide adaptability and stability in the assessed environment. These lines could be released as new cultivars.