Trichopria drosophilae (Perkins) (Hymenoptera: Diapriidae) is a pupal endoparasitoid of Drosophila spp. (Diptera: Drosophilidae) that is currently considered for biological control of the invasive fruit pest Drosophila suzukii (Matsumura). Field samplings in Europe have revealed that T. drosophilae is common in the South, whereas only a few records from north of the Alps exist. In Northern Italy and Southern Switzerland adults of this species have been recorded from July onwards, when populations of D. suzukii often have reached considerable sizes already (Mazzetto et al., 2016; Knoll et al., 2017). An effective area-wide control of D. suzukii would need to target populations earlier in the season when they are still low (Rossi Stacconi et al., 2018). To assess to which extent T. drosophilae is able to withstand winter conditions in the north of Switzerland and whether it could survive frost events during spring releases, we looked into its cold tolerance.