Investigations have been carried out to evaluate the two-phase frictional pressure drop for air non-Newtonian liquid flow through helical coils in horizontal orientation. The experiments performed using 36 different helical coils and 4 different concentrations of sodium salt of carboxymethyl cellulose (SCMC) as non-Newtonian liquids. The effects of air and liquid flow rate, coil diameter, helix angle and liquid properties on two-phase frictional pressure drop have been discussed. An attempt has been made to fit the experimental two-phase frictional pressure drop data by the Lockhart and Martinelli, Chem. Eng. Prog. 45, 39-48 (1949) correlation and the modified Lockhart-Martinelli correlation as presented by different authors. In another approach, friction factor method was adopted to correlate the experimental data by dimensional analysis. The correlation developed predicts the two-phase frictional pressure drop with acceptable statistical accuracy.