The effect of six crop rotation systems, planted under conventional and reduced tillage, on root and stalk rot and grain yield of sorghum was studied. The systems were applied for five seasons until 1991/92 when the effects of the systems were compared. Neither tillage, nor rotation, or the interaction of both had a significant effect on sorghum root rot. Stalk rot at harvest was significantly lower and grain yields significantly higher with minimum tillage (main effect) compared with conventional tillage. No significant rotation effect or tillage×rotation interactions were observed for both variables.