Overall response to flotation of coal fines is improved by using mixtures of pine oil and methyl isobutyl carbinol as frother instead of either of them alone. Measurements of static froth height and surface tension of aqueous solutions of the frother are used to study the synergistic effect and to arrive at an optimum frother composition. The observations made in these studies are confirmed by flotation tests with coal fines from a coking coal washery using flotation columns of 100 and 220 mm diameter operating at nominal capacities of 20 and l00 kg hr−1respectively.