One of important issues in plant breeding is a determination of interrelationships of traits for which selection is done. The trial was set up with 15 maize hybrids, in six locations, two sowing densities and during two years. The aim of the study was to establish if the same yield components had the crucial effect on the yield in different sowing densities. Two main factors belonging to the set of correlated yield components were extracted by the factor analysis in both sowing densities and they encompassed 60.6 and 60.9% of variability. They were in the highly significant correlation (p<0.01) with yield in both sowing densities (0.81 and 0.70 first factor and 0.28 and 0.44 second factor, respectively). In the trial with a lower sowing density, the first factor (47.87% of the variance) was in the greatest correlation with plant height, ear height, ear length and number or kernels per row. In the trial with a higher sowing density, the first factor (47.91%), was in the greatest correlation with ear and cob diameters and grain moisture. Low estimates of the correlation for the number of kernel rows, concerning both factors and both sowing densities, point out that this trait does not share the same structure with the other yield components, and cannot be explained by the factor model. These results point out to the different selection criteria that should be favoured in breeding maize hybrids for various sowing densities.