The preparation and crystalline features of perovskite solid Solution Y(CoxMn1-x)O-3, x = 0.6 and 0.7, belonging to the Co-rich region of the pseudobinary system YMnO3-YCoO3 have been studied. Dilatometric experiments performed under different atmospheres have been carried out for determining the best conditions to obtain single-phase samples. The influence of the thermal cycle and of the sintering density on the appearance of secondary phases has also been established. Firing in O-2 atmosphere favors the formation of the pure perovskite. The cooling rate plays an important role for inhibiting the formation of secondary phases. All of the parameters depend ultimately on the final density of the polycrystalline bodies.