To stimulate budbreak and enhance fruit maturation of Cardinal and Perlette grapevines, H2CN2 was applied at 2.5, 5.0 and 7.5% (v/v) on hard wood cuttings and mature vines. The application ofH2CN2 to one node cuttings induced a hastening ofbudbreak by about 5 weeks for Cardinal and 3 to 5 weeks for Perlette. Total number of buds that burst was slightly increased for both cultivars when compared to the controls. On mature vines, H2CN2 was applied on two dates (42 or 30 days before estimated date of normal budbreak). The first application date advanced budbreak by 25 and 5 days for Cardinal and Perlette, respectively, while the second application date enhanced budbreak by 19 days for Cardinal and none for Perlette. Vines sprayed with H2CN2 showed an increase in yield, cluster number and berry weight. Soluble solids were significantly (p <0.05) increased while the acidity was significantly decreased, reflecting an earlier maturation ofberries from the treated vines at harvest. Keywords: Growth regulators - Budbreak - Berry maturation - Vitis vinifera L.