Farming in the rainfed lowlands of northwest Luzon, Philippines, is highly intensive, diversified, and commercialised. The cropping-system is predominantly rice-based in the wet season and high-value cash crops are grown during the dry season. Using panel data from 100 randomly selected farmers, a stochastic input distance function is used to investigate scope economies in this environment. Results show that significant scope economies exist between rice and the major dry-season crops of garlic and mungbean. Scope diseconomies exist between rice and maize.