Growth modes of thin films on a solid surface are studied by using a Solid-On-Solid model. Monte Carlo technique is used to simulate adsorption, desorption, and diffusion processes of the solid-vapour interface. The emphasis is on the Stranski-Krastanov growth mode which is a combination of Frank-van der Merve and Volmer-Weber growth modes. Inclusion of an anisotropy factor into the attractive surface potential leads to an initially layerwise growth, which abruptly turns into growth of separate islands. This is characteristic of Stranski-Krastanov growth. The growth mode is verified from snapshot pictures of the growing surface and from the time evolution of the surface roughness as measured by the standard deviation of the layer thickness.