Анотация: In 2010 the content and composition of the essential oil from Rosa alba L. in the different phases of the development of blossom is examined. Quantitative and qualitative changes of the essential oil are traced. Flowers from the population of white rose in 6 phases were investigated. The study was conducted at the Institute of roses and essential oil plants Kazanlak. It was found that optimum for the quantity and quality of the essential oil is not exactly at one time, but there is a correlation between the two indicators. The maximum content of essential oil is in phase IV - in semi-opened petals (in percentage)