Experimental investigations have been carried out to evaluate the holdup for gas-non-Newtonian liquid flow through helical coils in vertical 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 intermittent flow regime was observed in the experiments. The effects of gas and liquid flow rate, coil diameter, helix angle, and liquid properties on the holdup were illustrated. An attempt has been made to fit the experimental holdup data by the Lockhart and Martinelli (Chem. Eng. Prog. 1949, 45, 39-48) correlation and the modified Lockhart and Martinelli correlation as presented by different authors. In another approach, a correlation was developed to predict the holdup as functions of the physical and dynamic variables of the system. Statistical analysis of the correlation suggests that they are of acceptable accuracy. © 2006 American Chemical Society.