As ornamental plant originated from Central America, Datura inoxia Mill. has been introduced to many areas beyond its natural range. However, in many places, mainly in the Mediterranean region D. inoxia has escaped from cultivation and is being established as an alien. In relevant botanical literature its occurrence on the Balkan Peninsula has not been reported for Albania, Bosnia & Herzegovina, Macedonia (FYROM) and Serbia. Based on our field and herbarium studies, we have found that D. inoxia is also present in Serbia, both as cultivated ornamental plant, but as well as an escape, with established populations. We have registered this species in 23 localities in Srem, Bačka, Banat, Šumadija and NE Serbia regions, which are situated in 16 UTM 10 km x 10 km squares. Most of the findings (16 localities) refer to a small group of individuals which are cultivated, while the remaining seven relate to plants that have escaped from cultivation and have established small wild populations in the surrounding ruderal habitats, edges of natural or planted forest, waste and arable fields. Although we have registered only seven small groups of individuals that have escaped from cultivation, due to its capacity to invade natural habitats D. inoxia can be considered as potential threat for natural biodiversity in Serbia.