[en] Entrainment of liquid droplets in vapour or gas is frequently encountered in gas-liquid contactors and in vapour generators, such as reboilers, evaporators, trays of distillation column, etc., due to an incomplete separation of the two phases when the vapour leaves the liquid. Entrainment lowers the efficiency of the equipment as well as the quality or purity of the product. The authors have done a dimensional analysis of the variable involved and carried out experiments to evolve a correlation. The dimensionless correlation so obtained is given