The approach of dispersed droplets in molten quiescent polymer blends from an initial distance comparable with their radii was analysed. It was shown that a substantial flattening of the droplets appears only at distances comparable with the critical distance for rupture of the matrix film between droplets. The time of coalescence is controlled by the film drainage between practically undeformed spherical droplets. The effect of viscoelasticity on the rate of coalescence was studied for the Maxwell model of the matrix. It was shown that the rate of coalescence increases with increasing relaxation time of the matrix. The theory of coalescence caused by Brownian motion or molecular forces predicts rates of coalescence which are comparable with those determined experimentally. Neglecting synergism between the Brownian motion and molecular forces, approximations used in the description of droplet distribution and neglecting the simultaneous approach of three or more droplets still limit the applicability of the theory for a quantitative prediction of coalescence rate.