Although molasses is extensively used in the animal feed industry in South Africa, there are conflicting views on its value as an energy source, Because of its low cost in relation to that of maize and in view of the increasing demand for energy-rich grains in the feedlot industry, it is imperative that the value of molasses as an inexpensive substitute for maize meal should be investigated. With this purpose in mind, two experiments were planned In which 0%, 7%, 14% and 21% molasses, expressed on a complete diet basis, was used to replace maize meal. In one experiment 4 groups of cattle were fed complete diets while in the second experiment a concentrate mixture and roughage were fed separately. In addition, the effect of vitamin A injections on mass gain was investigated. The replacement of maize meal with up to 21% molasses did not influence rate of live mass or rate of carcass mass gain significantly. Molasses improved acceptability of the experimental rations so that the feed conversion rate on the highest molasses level was noticeably poorer. There is some evidence that molasses, at an intermediary level, may improve rate of gain and feed conversion rate. Vitamin A injections did not have a significant effect on any of the parameters investigated. With the present wide price differential between molasses and maize meal, the use of molasses or molasses meal as an energy substitute in feedlot rations has considerable economic merit.