A dimensionless correlation for gas hold-up in a bubble column filled with pure liquids and binary mixtures has been developed. The criteria of bubble coalescence in pure liquids and foamability of binary mixtures have been included successfully in the proposed correlation. For the first time, comprehensive data of gas hold-up with respect to concentration in four binary systems are presented. The often-reported enhancement of gas hold-up in aqueous alcohol mixtures has been observed experimentally. The proposed correlation is able to predict successfully the trend of gas hold-up enhancement with respect to concentration. The estimated values are found to be within 7% of the measured values.