Experimental investigations have been carried out to evaluate the two-phase pressure drop and the hold-up for gas-liquid flow through vertical helical coils. The coils were made of thick-walled transparent PVC tubes of diameters 0.01 and 0.013 in. Twenty-four coils were made with different coil diameters and different helix angles (0-12degrees). Three different liquids and air were used for the experimental studies. Empirical correlations were developed to predict the two-phase friction factor and the liquid hold-up as functions of the physical and dynamic variables of the system. Statistical analysis of the correlations suggests that they are of acceptable accuracy.