An experimental study for continuous separation of concentrated bidisperse suspensions in a vertical settler has been conducted. The bidisperse suspension examined consisted of light polystyrene beads and heavy polyvinyl chloride beads in a salt solution. The effects of the feed total solids concentration, feed flow rate and split ratio (defined as the ratio of either the underflow or the overflow to the feed flow rate) on the performance of the settler were examined. A zone having strong lateral nonhomogeneities in the form of instabilities (fingers) was observed in the settler for a feed having high total solids concentration. The size of the instability zone was found to be a strong function of the split ratio and feed flow rate. The presence of these instabilities significantly improved the performance of the settler, especially at low feed flow rates. For low feed total solids concentration, a previously developed kinematic model which assumes a uniform lateral concentration profile, i.e., in the absence of local instabilities, was found to predict the experimental measurements well. For high feed total solids concentration where strong local instabilities occur, the model is used to assess the effect of the local instabilities on the performance of the settler.