Sweet cherries (Prunus avium) can be one of the most profitable tree fruit cultivated in temperate climates. While cherry trees grow naturally to relatively tall heights, new size-controlling cherry rootstocks similar to those used in high-density apple orchards are now a reality. The Gisela series from Germany, the Gran Manier series from Belgium, the Weiroot series, the P-HL series, Tabel Edabriz, and others of international origin are at various stages of scientific and field testing in North America, with some now moving into commercial fruit production. These stocks confer several highly advantageous traits besides vigor control, including precocious fruiting and high productivity. While these obvious traits are exciting, serious problems have also been documented, on occassion, with such phenomena as small fruit size and tree decline. As many of these rootstocks are interspecific Prunus hybrids, might there be significant limitations for fruit quality and orchard longevity? What is known about their susceptibilities to pathogens and pests? What is known about their tolerance to various soil types and/or climatological stresses? Further, with the U.S. and worldwide orchard area planted to fresh-market sweet cherries already expanding to record levels throughout the 1990s and a time-honored agricultural trend toward overproduction until grower profits are minimized (see recent international apple markets), what might be the future impact of such precocious, productive rootstocks on sweet cherry profitability and sustainable production? This overview will address these topics, providing some answers and some areas for future scientific investigation and discussion.