Several alternative techniques have been proposed in the literature to efficiently locate particles within unstructured grids. The present paper reviews two recently published, particle-locating algorithms, and introduces a new approach which improves the performance of the previous methods. The proposed algorithm is valid for arbitrary two-dimensional (2D) or three-dimensional (3D) grids, it is simple to implement, and results in fairly small CPU-time requirements. Furthermore, the directed-search feature of the present method offers shorter search paths and allows the detection of walls during the tracking of the particle trajectory. The performance of the proposed particle-locating strategy is compared with existing ones, and is evaluated on two tests, namely a 2D/3D random particle-locating test and a 2D Lagrangian simulation of a premixed turbulent flame. (C) 2002 Elsevier Science Ltd. All rights reserved.