A model for particle settling velocities in polydisperse suspensions is proposed alongside normalized particle self and interaction mobilities. The model predictions are compared with other models (Davis and Gecol, 1994; and Al-Naafa and Selim, 1980), is well as published experimental data. A general agreement was found between the current-model and the existing data for binary dispersed particle systems except for one case where phi(L) is fixed. For ternary dispersed particle systems, predictions from both the A-S model and the current model agree well with the existing data. With the improved sedimentation coefficients, the D-G model also produces satisfactory results.