BACKGROUND: Thermography permits non-invasive examination and presentation of cutaneous temperature differences. When planning microvascular flaps, thermography may illustrate these differences and may portray patterns of blood circulation near to perforators. As an additional tool, thermography may enhance quality and diversity in free flaps. PATIENTS AND METHODS: In this prospective study, we examined 10 patients with 13 free DIEP-flaps for breast reconstruction. With smartphone-based thermography, we analysed preoperative abdominal "hot spots" of skin circulation (entrance of perforators). The results were compared with preoperative computed tomographic angiography (CTA) and intraoperative anatomical findings. RESULTS: Thermography was succesfully performed on all patients. Areas of perfusion were reliably shown in the raised area ("hot spot"). Each perforator selected by thermography was also selected for the DIEP free flap on the basis of intraoperative findings. Moreover, the identified main perforators were identical to perforators found at the CTA. CONCLUSION: Smartphone-based thermography provides an easy, rapid and non-invasive method to present cutaneous differences in temperature. "Hot spots" can reliably illustrate the entrance of perforators. When selecting a suitable perforator, thermography provides additional information for imaging perforator-based flaps.