The influence of three interstocks on the growth of 7-9-year-old trees of the sweet cherry cultivars Biggareau burlat and Stella grafted on Prunus mahaleb L. – P1 seedling rootstock during the 2012-2014 period was tested. The Gisela 5 rootstock, the North Star sour cherry cultivar and Hybrid 2/10 were used as interstocks, each of them being 10cm and 30cm long. The same sweet cherry cultivars grafted directly on P1 were used as control. The control had the thickest trunks in the zone of rootstock. In terms of trunk thickness in the scion zone the control surpassed only the variants with short interstock. It was established that under the influence of longer interstocks the trunk thickness was reduced in the zone of the rootstock and the interstock, but it was increased in the zone of the scion, and the differences were significant mainly with Gisela 5. The crown volume of the Bigarreau burlat cultivar with interstock was reduced compared with the control, while the use of a longer interstock made the reduction larger. The highest values of one-year shoot growth was recorded in the control, while in the other variants higher values of one-year shoot growth was recorded in the trees with short interstock compared with those with long interstock although the differences were not always significant. Trees with longer interstock had significantly more suckers than those with shorter interstock but the suckers formed by the control were almost nil.