This year's field data confirmed the success of our reintroduction action aiming to establish a viable population of Polyommatus thersites in Prague. We observed several dozens of new individuals appearing in spring (the first generation) in Dívčí hrady and we added additional ca. 30 individuals from the české středohoří region. In the summer (the second generation), several hundred individuals were observed on the site and P. thersites became the second most abundant species among local butterflies. We firmly believe that the population of P. thersites will continue to do well, and we want to contribute to this by taking active care of the Dívčí hrady site.