During the period 2004-2007 in the rose plantations in the region of Plovdiv a new unknown for producers mycotic disease appeared. As a result, yield losses varied between 5-10%, and even higher. Small, purple, roundish spots appear on rose leaves. They become whitish-grey with a reddish margin afterwards. In the case of a severe disease attack leaves drop down. Symptoms can be found also on leaflets and at the base of the flowers. On the plant shoots spots are roundish to elliptical, reddish in color with acervulae on them. The causal agent of the disease has been isolated and identified as Sphaceloma rosarum. Two types of spores are formed in the acervulae – the first type are elliptical, elongated, slightly curved with one vacuole at the edges (7.65-8.42 X 1.74-3.82 μm); the second type are thread-like, slightly curved at one of the edges. Mycelia growth and spore germination have been registered in the temperature interval 5-6o to 30-32oC. The pathogen over winters in infected plants as mycelia, aservulae and sclerotia-like structures. „In vitro” fungicidal effect on mycelia growth is achieved with tiophanate methyl, hexoconazole, triadimefone, tebuconazole, micobutanyl, etc.