Farmers in the tropics do not usually practise monocropping, but commonly practise intercropping. These farmers are not certain of the specific benefits of crop mixtures. If growing maize with pulses would be beneficial, efforts should be made to determine which grain legume should be the companion crop. The objective of this investigation was to determine the effects of intercropping groundnut (Arachis hypogaea L.) or sugar bean (Phaseolus vulgaris L.) on crop mineral concentrations and maize yield. The field investigation was conducted on a acid highly weathered Oxisol in Swaziland. Maize was grown as a monocrop, and in association with sugar bean and groundnut. Five treatments were arranged in a randomized complete block design replicated four times. Results showed that there were no significant differences in the concentrations of nutrients in maize stems and leaves, though maize leaves contained higher concentrations of minerals than maize stems. However, these plant analyses revealed surprising low levels of N, P, K, S, and possibly B in maize and groundnut as would be expected when grown on an Oxisol soil. The reason for the considerably higher levels of these minerals in sugar bean in not known. Maize yields were: maize intercropped with groundnut, 6146 kg ha-1; pure maize, 6298 kg ha-1; maize intercropped with sugar bean, 5806 kg ha-1. It is recommended that for increased total crop yields/plot, farmers intercrop maize and groundnut in preference to maize and sugar bean.