The kinetics of two dimensional homo- and heterocoagulation of particles of equal size were investigated by Monte Carlo simulation using a square lattice and particles with a functionality of four. In both processes, a size-dependent cluster aggregation ability gamma allowed simulation of diffusional and reactional limited processes. In heterocoagulation, determination of the effects of the relative concentration x of the particles A and B and the cluster aggregation ability on the aggregation rate provided information concerning the influence of the frequency of unsuccessful encounters between identical particles on the temporal increases in the weight S(t, x, gamma) and number N(t, x, gamma) average sizes of the dusters. Dynamic scaling exponents for the temporal variations of the average cluster sizes were found to be linear or power law functions of the composition x.