As biofuel projects may be associated with positive and negative effects on people's health and wellbeing, a health impact assessment was performed for the Addax Bioenergy Sierra Leone (ABSL) project. We present data from the baseline health survey, which will provide a point of departure for future monitoring and evaluation activities.; In December 2010, a cross-sectional survey was carried out in eight potentially affected communities. A broad set of clinical and parasitological indicators were assessed using standardised, quality-controlled procedures, including anthropometry and prevalence of anaemia, Plasmodium falciparum and helminth infections.; Complete datasets were obtained from 1221 individuals of 194 households and eight schools. Of children aged <5 years (n=586), 41.8% were stunted, 23.2% were underweight and 4.8% were wasted. Very high prevalences of anaemia and P. falciparum were found in children aged 6-59 months (n=571; 86.1% and 74.0%, respectively). Overall, 73.7% of women of reproductive age (n=395) were anaemic. In school-aged children (n=240), 27.9% had light- to moderate-intensity hookworm infections, whereas Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni were rare (<3% each).; The detailed description of the baseline health conditions, in combination with future health surveys, will deepen the understanding of how a biofuel project impacts on community health in a rural setting in sub-Saharan Africa.