Two field experiments were conducted in Kenya to investigate the effects of weed control on the yield and forage quality of newly introduced cold tolerant high altitude sorghums, using weed control methods in current use for maize production. All methods of weed control yielded considerably more than the control. The pre-emergence application of atrazine at 2·0 kg a.i./ha was the preferred method, and the sorghum cultivars studied proved tolerant to this rate of application. When plant population were reduced by herbicide toxicity, the surviving sorghum plants produced more tillers, thus partly offsetting the effect on yield. Cultivars with a genetic ability to produce many tillers had an advantage over those which tiller less readily. It was shown that the grain type cultivars studied belonged to the second group, while the forage type sorghums belonged to the first.