An experiment was conducted on-station at the National Semi-Arid Resources Research Institute [NaSARRI], Serere in Eastern Uganda during the first and second rainy seasons of 2011. The objective of the experiment was to determine the effects of plant density on the performance of elite cowpea varieties. There were three plant densities [74,074 plants/ha at 45 cm × 30 cm; 55,555 plants/ha at 60 cm × 30 cm and 44,444 plants/ha at 75 cm × 30 cm]. These are referred to as high, medium and low plant densities, respectively. In addition to the three plant densities, there were four elite cowpea varieties; IT85F-2841 [spreading], MU-93 [spreading], MU-93 [erect], IT82D-889 [erect], and two local cowpea varieties; Ichirikukwai [spreading], and Ebelat [erect]. This was a factorial [3 × 6] arrangement in a randomised block design [RCBD]. The experiment was replicated three times. Data were collected on growth and yield parameters. Results indicated that elite variety IT82D-889 significantly [P< 0.05] flowered, reached physiological maturity earlier and gave the highest grain yield which was 952 kg/ha and 1163 kg/ha during the long and short season, respectively. Medium plant density [60 cm × 30 cm] gave consistently high grain yield which was 657 kg/ha compared to the high and the low plant densities that yielded 578 kg/ha and 565 kg/ha, respectively. The yield differences among plant densities were not significant. The mean yield of local varieties compared to those of elite varieties were 562 kg/ha and 684 kg/ha for Ebelat, and 519 kg/ha and 944 kg/ha for Ichirikukwai during the short and long season, respectively. Correlation coefficients between various growth parameters, yield and yield components were weak. However, correlation coefficient between days to 50% flowering [n-2 = 52] was -0.3006 and significant [P< 0.05], indicating that 9.0% of the differences in seed yield could be attributed to reduction in the number of days to 50% flowering. It is concluded that elite cowpea variety IT82D-889 should be adopted because of its earliness and high yielding potential.