with the objective of increasing yields and fruit quality of cv. flamecrest peaches, a cultivar with high chilling units demand, the present experiment was conducted in an orchard near to the farroupilha city, in the year 2000. the hidrogen cyanamid and mineral oil were applied in two different times: middle of july and begining of august. the dormancy breaking, flowering, fruit set, yield, and antecipation of harvest were evaluated from plants of the folllowing treatments: 1,22; 2,45; 3,675 or 4,90 g of i.a.l-1 hydrogen cyanamid together with 10 g i.a l-1 of mineral oil or a single application of 10 g i.a l-1 mineral oil. the control plants were not sprayed with the dormancy breaking treatment. none of the treatments resulted in sprouting antecipation of flowering buds however, plants treated with 1,22 or 4,90 g i.a l-1 hydrogen cyanamid mixed with 10 g i.a l-1 mineral oil, had a higher number of sprouted vegetative buds. there was no significant effect of the period of application on flowering and fruit set. the number of fruits thinned out from each plant was higher for the treatments with 2,45 or 4,90 g i.a l-1 of hydrogen cyanamid mixed with 10 g i.a l-1 of mineral oil. when applied to peaches trees in july, the treatments with 1,22 and 3,675 g i.a. l-1 of hydragen cyanamid and 10 g i.a. l-1 of mineral oil resulted in a higher number of fruits and total yield per plant. all the treatments, in the second apllication period, produced higher yields. the average fruit weight, total soluble solids and pulp firmness were not influenced by the treatments.