AN ANALYTICAL MODEL OF THE FLOW AND SEDIMENT CONDUCTION THROUGH A VORTEX TUBE HAS BEEN DEVELOPED HEREIN. THIS MODEL COMBINES THE SPATIALLY VARIED FLOW EQUATIONS WITH THE SEDIMENT TRANSPORT MODEL IN SAND BED CHANNELS. THE EMPIRICAL COEFFICIENTS INTRODUCED IN THE MODEL HAVE BEEN INVESTIGATED WITH THE HELP OF ROBINSON'S 8-FT. FLUME DATA (10). IT IS FOUND THAT THE COEFFICIENTS OF VELOCITY CV, OF AREA CA AND OF LATERAL MOMENTUM INFLOW CIL CAN BE CONSIDERED AS CONSTANTS FOR THE TUBES INVESTIGATED BY ROBINSON. HOWEVER, THE VORTEX FLOW COEFFICIENT, CI IS FOUND TO BE A FUNCTION OF THE TUBE GEOMETRY AND THE FROUDE NUMBER OF FLOW ON THE TUBE. KNOWING THE CI - IF RELATION FOR A SPECIFIC TUBE GEOMETRY, IT IS POSSIBLE TO USE THIS MODEL TO INVESTIGATE VARIOUS CHARACTERISTICS OF THE VORTEX TUBE FLOW. THREE NUMERICAL EXAMPLES HAVE BEEN USED TO SHOW THE VERIFICATION OF LABORATORY STUDY DATA, AND THE EFFECT OF VARIATION OF PARAMETERS ON THE SEDIMENT CONDUCTION THROUGH THE TUBE.