This paper describes inoculation procedure and assessment scales developed for the field evaluation of resistance to four major diseases of cowpea in the savanna belt of tropical Africa. Using these techniques, sources of combined resistance to bacterial blight (Xanthomonas vignicola), cab (Sphaceloma sp.), brown blotch (Colletotrichum spp.) and Septoria leafs pot were sought both among germplasm accessions known to possess resistance to other diseases and in improved breeding lines of cow pea (Vigna unguiculata). One line, VITA-4, was found to have resistance to all four diseases while six other lines had resistance to two of the four diseases. Several of the lines additionally possess resistance to cowpea aphid-borne mosaic virus which is also widespread in the savannas. The approach may lay the basis for the ecological stratification of breeding for disease resistance in cowpea, ultimately assisting in the development of comprehensive, durable resistance within each ecological zone.