The aim of our study was to simultaneously determine the parasitism rates of C. ohridella pupae in Istanbul and in Belgrade. Collection of the pupae in Istanbul was carried out on three occasions, 12th of June, 3rd of July, and 1st of August, respectively, corresponding with the three generations of the leafminer per year. In Belgrade, samples were collected only during the spring generation of the leafminer, in the period from 7th to 11th of June, 2017. Severe drought stress of horse chestnut trees impaired development of the 2nd and the 3rd leafminer generation and made it impossible to collect reasonable numbers of Cameraria pupae after the first collection date. At each collection date, 150 pupae per location were taken and treated as independent factors and their influence on the parasitism rates of the C. ohridella pupae was examined using the two-way ANOVA. The parasitism rates of the C. ohridella pupae in Istanbul ranged from 16 to 28% at the 1st collection date, from 18 to 20% in the 2nd collection date, and from 4 to 8% in the 3rd collection date. Parasitism rates in C. ohridella pupae collected in Belgrade ranged from 0 to 12%. The majority of them (80%), however, were parasitized to a low level of 0 to 4%, only.