A number of relationships are given in the literature for estimation of the drag coefficients; however, most of these are applicable only for a narrow range of Reynolds number (Re). Some new empirical relationships are proposed in this study to estimate the drag coefficients in the flow of Newtonian liquids around the solid spherical or cylindrical particles and the deformable particles. An approximation series approach is used to develop these empirical relationships. It is shown that the proposed relationships can be applicable for the solid spherical or cylindrical particles in the range of 0.1 > Re > 10(6), and for the deformable particles (drops and bubbles) in the range of 0.1 > Re > 10(4). The predicted coefficients are in a good agreement with the experimental data given in the literature. (C) 2001 Elsevier Science B.V. All rights reserved.