This work was aimed to evaluate the consequences of selfing over the selfed female parental, in hybrid corn seed production. Hybrid seeds and selfed female parental seeds were produced from the single hybrid C 901, the three way hybrid C 808A and from the two double cross hybrids C 425 and C 701. After obtaining the material the components of the hybrid seed lots showing a mixture of seeds derived from the selfed female parental, on rates of: 0, 5, 10, 20 and 100%, were evaluated in four places in the state of São Paulo (Piracicaba, Paranapanema, Guaira and Ituverava). Considering the four studied hybrids, there was a 0,5% reduction on the grain production to each 1% of seeds derived from selfing mixed with the hybrid seeds. The reduction, result of the mixture, on the grain production rate of the hybrids studied, depended, after alI, on the production rate of the plants derived from selfing and also on the compensation capacity of the hybrid plants. The plants derived from selfing showed themselves shorter, with lower spikes height and less productive than the hybrid plants.