It was the objective of this Master`s thesis to examine whether the application of ammoniumthiosulfate (ATS) on four sorts of cherries had a sufficient thinning-out effect and, thus, led to quality enhancement of the remaining fruits. Durind the vegetation period of 2007, a test was executed in the fruit-growing test centre at the University of Natural Resources and Applied Life Sciences in Vienna, Austria. The following treatment variations were examined on the sorts Blaze Star, Samba, Merchant and Techlovan: Application of 17,64 g/l ATS on blossoms open by 40% and application of the same amount on blossoms open by 80%, resdpectively. Those two treatment strategies were compared to each other as well as to an untreated variation regarding a thinning-out effect and the possibility of a related quality enhancement. Data evaluation showed that treatment variations had not affected all examined parameters. While ATS application didn`t influence fruit fall, a significant impact of the respective sorts on fruitfall was proved. Harvest volumes were significantly reduced by the thining-out effect of ATS. In this manner fruit weight as well as fruit size increased significantly. Besides, a significant impact of sorts on harvest volumes, fruit weight, and fruit diameter was shown. An impact of sorts and thinning-out on the pH value was also found out. While the soluble dry substance and anthocyane content was not affected by thinning-out, a signifuicant impact of sorts on the soluble dry substance and anthocyane content of the fruits was ascertained. The content of titrable acid was significantly influenced by treatment variations as well as by sorts. ATS based thinning-out caused slight leaf burns.