New psychoactive substances (NPS) continue to appear on the drug market and alpha-pyrrolidinoisohexanophenone (α-PiHP) is one of the most popular cathinone derivatives. In this paper, we report a case of death caused by α-PiHP. Based on the toxicological results of the studied case along with autopsy, histopathological findings and crime-scene information, fatal intoxication with α-PiHP was accepted as the final cause of death. α-PiHP and its metabolite (OH-α-PiHP) were detected and quantified in all post-mortem materials (blood collected from the heart, the femoral vein and the dural venous sinuses, vitreous humour, cerebrospinal fluid, cerebral cortex, brainstem, cerebellum, bile, liver, kidney, heart, pancreas, spleen, thyroid gland, lung, adipose tissue, stomach and intestine). To date, this is the first case of determination of α-PiHP and its metabolite in post-mortem specimens. In our opinion, α-PiHP and its metabolite concentration database can be helpful in the interpretation of fatal cases.