In 2015 and 2017, potato storages were surveyed for the prevalence of atypical potato tuber rots in Nevşehir and Isparta Provinces of Turkey. About 4–5 months after harvesting, 80% of the potatoes cv. Melody, that were stored at 4–5 °C and 65–75% relative humidity, were affected by the disease. The symptoms of the disease were similar to gangrene caused by Boeremia exigua var. foveata including superficial, dark lesions or dark brown, sunken lesions that have a sharp border with healthy tissue on tubers. A fungus was consistently isolated from necrotic tuber tissues. The pathogen was identified as Colletotrichum coccodes (Wallr.) Hughes based on morphological characteristics and the analysis of sequence of the internal transcribed spacer region of the rDNA. Pathogenicity was tested by tuber inoculation with mycelial agar discs. After 4–6 weeks, irregular and dark brown sunken lesions developed on potato tubers, while control tubers remained symptomless. This is the first report of C. coccodes that caused extraordinary symptoms on potato tubers in Turkey.