Inadequate winter chilling periodically becomes a serious problem for the commercial peach industry in the Southeast, especially along the Gulf Coast. A number of countries around the world are using hydrogen cyanamide (Dormex-SKW) to replace lack of chilling in peaches and other fruit plants. Studies were conducted over 3 years (1990-1992) to evaluate the effects of hydrogen cyanamide on replacing lack of winter chilling in 'Ruston Red' peach, (850 hour chill requirement). Findings indicated full tree sprays in early fall and late winter (after buds had become active) caused excessive bud thinning and crop reduction. Applications made when 65 to 85% of chilling requirement was satisfied (no visible bud activity) were very effective at concentrations of 0.5 to 1.0% V/V of 49% Dormex. Rates above 2% were very toxic causing crop loss. Dormex effectively replaced a shortage of 265 chilling hours of 'Ruston Red' during one season resulting in full cropping while controls failed to crop.