A preliminary screening experiment was conducted to evaluate 47 cowpea [Vigna unguiculata, (L.) Walp.] genotypes for use as a weed-suppressing cover crop. Lines evaluated in this study included forage varieties, PI accessions, experimental breeding lines, and land races of unknown origin. Of these, 11 were selected for further testing on the basis of vigorous growth and weed-suppressing ability. In a field experiment repeated over 4 years, the selected genotypes were not different from the leading cover crop cultivar, `Iron Clay', in biomass production. Vigor ratings, vine growth ratings, and canopy widths of some genotypes exceeded those of `Iron Clay'. Vigor ratings and canopy measurements were efficient selection criteria that could be useful for breeding cover crop cowpea cultivars. All selections except an African cultivar, `Lalita', were highly resistant to southern root knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood], and the genotypes varied in seed size, photoperiod, and response to diseases.