The study was carried out to investigate the susceptibilities of some improved cowpea genotypes to infection and damage due to bacterial blight, smut and cowpea aphid-borne mosaic virus CABMV in a sorghum-based cropping system during 1999 and 2000 at Minjibir, Kano, Nigeria. Treatments consisted of six (6) genotypes made up of one (1) local Danila and five (5) improved (IT90K-277-2, IT95K-1090-3, IT95K-222-14, IT96D-666 and IT96D-759) and in a four (4) row arrangements (1S:1C, 2S:2C, 1S:2C, and 2S:4C, reflecting millet to cowpea rows). These were laid out in a split plot design with three replications. There was a significant effect (P < 0.05) of cowpea genotype on bacterial blight. In both seasons IT96D-666 recorded the highest for bacterial blight and smut damage. In 1999, Danila along with improved genotypes recorded lower ratings for blight, while in 2000 only Danila and IT95K-277-2 recorded the highest protection against bacterial blight. For smut with the exception of IT96D-666, the other (Danila, IT95K-277-2, IT95K-1091-3, IT95K-222-14 and IT96D-759) recorded statistically comparable lower damage ratings. In both seasons IT95K-277-2 recorded the least incidence and severity of leaf virus. Although the other genotypes had virtually similar and higher ratings in both or one of the two seasons, Danila and IT95K-1091-3 recorded consistently higher values. In the two seasons Danila produced significantly higher Total Dry Matter (TDM) and the other semi-determinate genotypes had comparable values. In both seasons IT95K-222-14 consistently out-yielded the other genotypes but it had statistically similar grain yield with IT95K-277-2 in 2000. Row arrangement had a significant effect on bacterial blight in 1999, whereas planting cowpea at 1S:1C recorded the least infection while the highest rating was obtained at 2S:4C row arrangement. Incidence and severity of leaf virus were not affected by row arrangement. In both seasons TDM and grain yields were significantly higher at 2S:4C while the least values were recorded at 1S:1C row arrangement was superior to the row arrangement. The genotype and row arrangement interaction indicated that planting of IT95K-222-14 at 2S:4C row arrangement produced the highest grain yield.