This paper reports an artificial neural networks (ANN) modelling programme for a light-duty diesel engine powered using blends of various biodiesel fuels with conventional fossil diesel. ANN was used here to predict nine different engine-out responses, namely carbon monoxide (CO), carbon dioxide (CO2), nitrogen monoxide (NO), unburned hydrocarbon (UHC), maximum pressure (P-max), location of maximum pressure (CAD P-max) maximum heat release rate (HRRmax), location of maximum HRR (CAD HRRmax) and cumulative HRR (CuHRR). Four pertinent engine operating parameters, engine speed, output torque, fuel mass flow rate and biodiesel fuel types and blends, were used as the input parameters for this modelling work. The feasibility of using ANN in predicting the relationships between these inputs and outputs were assessed. Simulated results were first validated against data from parallel engine test-bed study. Key effects of ANN "model" and "model parameter" such as type of transfer function, training algorithm and number of neurons, along with the methods of optimising the network settings were also presented in this paper. (C) 2011 Elsevier Ltd. All rights reserved.