The ongoing debate over the impact of biofuels on food security makes it difficult for governments to develop clear policies for an industry that can enhance rural employment and help to alleviate rural poverty, but may also reduce food availability and raise food prices. Whilst there have been many studies reporting a wide range of global commodity price impacts arising from the sharp rise in biofuel use over the past decade, there has been less evidence on food security impacts at a local level in developing countries. Where evidence does exist the impact is difficult to assess, often due to different types of production models and feedstocks, but also due to weaknesses in the methodologies and measures of food security used. This paper aims to help address this evidence gap by analysing household survey data from sites close to different types of biofuel operations in Mozambique and Tanzania, using an index that measures key macronutrient and micronutrient deficits at the household level. The results show that those households with employees in medium to large-scale biofuel feedstock operations achieved significantly higher food security outcomes than other households in the same locations. Furthermore, most of the households with better food security outcomes reported an improvement in food security since the biofuel operations had been established and attributed this mainly to increased and more regular income from salaried employment.