The possible benefits of molybdenum (Mo)-enriched seeds for grain legumes have yet to be addressed in sub-humid tropical areas, where cowpea (Vigna unguiculata L.) is an important crop. In 2016, seeds with 0.014 (low), 0.674, or 1.987 (high) μg seed −1 of Mo were harvested from plants sprayed with 0, 250, or 850 g ha -1 of Mo, respectively. These seeds were combined with either Bradyrhizobium inoculation (with or without) in 2017 or nitrogen (0 or 60 kg ha −1 ) in 2018 and evaluated under small farmer management in Maranhão State, Brazil. Maximum nodules plant −1 in these trials was 5.2. In 2017, inoculation acted synergistically with Mo-enriched seeds by increasing nodule weight. Averaged across inoculation levels, plants originated from high-Mo seeds had 36% higher leaf N concentration than those raised from low-Mo seeds. Inoculation did not affect yield, but plants grown from high-Mo seeds yielded 42% more than those raised from low-Mo seeds. In 2018, seed Mo content did not affect nodule and yield where urea was applied. However, without urea, plants raised from high-Mo seeds had 3.5-fold greater values for nodule number and weight and yielded 70% more than those grown from low-Mo seeds. We conclude that using Moenriched seeds associated with Bradyrhizobium inoculation would improve cowpea N nutrition and yield in a sustainable way.How to cite this article: Barbosa EPA, Sodré DN, Braun H, Vieira RF. Seeds enriched with molybdenum improve cowpea yield in sub-humid tropical regions of Brazil.