The separation of rehydrated Saccharomyces cerevisiae and an alkyl polyglycoside surfactant by column flotation was studied as a function of wash water flow and cation concentration. Separation of cells and surfactant was measured under steady-state conditions. Surfactant recovery in the foam concentrate was in the range of 86-95%. Yeast cells were enriched in the foam concentration by a factor of up to 11, but the recovery only reached 55%. The use of wash water was very effective for removing the cells from the foam, giving a good separation between the cells and the surfactant. Addition of chloride salts of Na, K, Ca, and Mg at concentrations in the range of 0.05-0.1 mol/L increased both the enrichment and the recovery of yeast in the foam. The most effective salt levels for cell flotation, less than 0.1 mol/L, were in the same range of concentration as the minimum electrophoretic mobility of the cells.