Very variable weather in the current changing climatic conditions, affects the establishment of the vegetation period of crops and exposes crops to failure, if farmers choose crops that are not adapted to relative maturity and that do not match the characteristics of the growing period. This study aimed to determine the relationship between the relative maturity of maize hybrids and grain yield and to determine the period of relative maturity that will support grain production in corn. In this experiment, a set of maize hybrids with different relative maturity were cultivated within the Institute of Crop Science „Porumbeni”, in the years 2020-2021. The total number of 200 maize hybrids were grouped into 4 maturity groups, entitled confirmed an approved native hybrid, depending on the relative maturity that ranged from 119 to 135 days. Maize hybrids were grown in optimal growing conditions. From the results obtained, it was observed that the control hybrids had a very low grain yield compared to the new hybrids experienced. In the first group, where 13 new hybrids were tested, the control hybrid Porumbeni 310, had 120 days until the relative maturation, and the grain yield was the lowest, namely 78.5%. In this group the new hybrids had from 119 to 124 days to full maturity, and the grain yield varied from 81.03% to 88.7%, which we can say that the grain yield of new hybrids was higher than the control, on average by 7.0%. The second group included 43 new hybrids and a control hybrid Porumbeni 374. The control hybrid had 122 days until full maturation and a grain yield of 80,7%, that is, 3% lower than the yield of newly experienced hybrids. The relative maturation of the hybrids in the second group varied between 124 and 128 days, 3 days longer than the control hybrid. The grain yield of new hybrids in this group was from 78.8% to 88,.5%. The third group registered 45 new hybrids and the control hybrid Porumbeni 427. The number of days until full maturation was 127-132 days, depending on the year of experimentation, and the control hybrid recorded 125 days until maturation. The grain yield in new hybrids ranged from 78.5% to 87.6%, while the control hybrid had a yield of 80.8%, lower on average by 4%, compared to the grain yield in new hybrids. The newly tested hybrids, the fourth maturity group, were witnessed by the local hybrid Porumbeni 461, which recorded 130 days until full maturation and a grain yield of 77.9%, and which was the lowest grain yield, from all experienced hybrids. In contrast, the new hybrids tested in this group had full maturation from 129 days to 135 days, and the grain yield ranged from 78.6% to 87.5%, which is 6% higher than the grain yield recorded at the control hybrid. On average, we recorded full maturation in the first group at 120 days, in the second group at 125 days, in the third group at 128 days and in the fourth group at 130 days. The average grain yield in each group was 84,6% in the first group, 83,6% for the second group, 83,9% in the third group and 83,6% in the fourth group, respectively. So, we can say that the obtained results showed an insignificant increase in grain yield in earlier maturing hybrids and an insignificant decrease in grain yield in later hybrids. This experiment showed that relative maturity had an insignificant impact on grain yield in maize hybrids, however, medium and semilate maturing hybrids had low grain yields