100 nm thick nanocrystalline cobalt films on Si(100) were studied quantitatively. The grains are densely packed and possess the average size (35.6±0.8) nm. The films have a texture with the hexagonal axis perpendicular to the film surface. The magnetic domains form a maze stripe pattern with the average size (102±6) nm. The domains are magnetized almost perpendicularly to the film surface.