The precipitation and deposition of crude oil polar fractions such as asphaltenes in petroleum reservoirs reduce considerably the rock permeability and the oil recovery. In the present paper, the model based on a feed-forward artificial neural network (ANN) to predict asphaltene precipitation of the reservoir is proposed. After that ANN model was optimized by unified particle swarm optimization (UPSO). UPSO is used to decide the initial weights of the neural network. The UPSO-ANN model is applied to the experimental data reported in the literature. The performance of the UPSO-ANN model is compared with scaling model. The results demonstrate the effectiveness of the UPSO-ANN model. Crown Copyright (c) 2011 Published by Elsevier B.V. All rights reserved.