We analysed the influence of the mode of participation in biomass production for biofuels on food security of different farm types. We studied two modes of participation in biomass production: an outgrower scheme for sunflower and a jatropha plantation offering full time employment and assessed the four dimensions of food security: availability, access, stability and utilization in smallholder farms in Central Mozambique. We interviewed 80 households who were participating in the sunflower outgrower scheme, had a household member working on the jatropha plantation or were not participating with biofuel production. For each household we quantified four indicators: maize sales minus purchases, gross revenue, revenue diversity, and household dietary diversity scores. Involvement of smallholder farmers with biomass production for fuel had a positive or no impact on the four dimensions of food security at the farm level. Positive food security impacts from working on the biofuel plantation were improvements in availability for the larger farms and improvements in access for the smaller farms. Utilization of food was generally not impacted. Impacts on food security from the sunflower outgrower scheme were minor. There is scope to improve the outgrower scheme with services and inputs that increase sunflower yields and give positive spill-overs to other crops.