This study examines the impact of contract farming with Farmer Organizations on farmers’ income. Contract farming with farmer organizations is a smallholder farmer-inclusive contract farming system. Field surveys were conducted in August 2010 with 75 farmers (including 39 contract farmers) in Kampong Thom province, Cambodia. The analysis—i.e., using a treatment effects model—indicates that contract farming with farmer organizations significantly raises farmers’ income. The econometric model and qualitative data show that the contract farming can attribute to an increase of farming productivity, quality of produce and farming cost efficiency.