A whole farm linear programming model, PRISM, was used to investigate the profitability of adopting a more intensive crop rotation in the central Mallee region of Victoria (annual rainfall 300-350mm). The model was optimised for farm profit with different amounts of working capital so that optimal proportions of a wheat-field peawheat- lupin rotation and a pasture-pasture-wheat rotation were included in the enterprise mix. Based on average yields from a 10 year rotation at the Mallee Research Station, Walpeup, increasing crop intensity from 33% of the farm to 77% of the farm increased annual profit by 38%. When the model was run again using typical input costs and average yields achieved in the region, intensification of cropping decreased annual profit by 86%. Average crop yields and wheat growing costs in the region were 20% lower than the Mallee Research Station, Walpeup. The analysis indicated that the profitability of more intensive cropping in this region is highly dependant on crop yields.