Galerina marginata is a wood-rotting fungus species belonging to the family Cortinariaceae within the division Basidiomycota. The species is widely distributed throughout the North America, Europe, Asia and Australia.Galerina marginata can cause mushroom poisoning resulting eventual death if not treated rapidly. Knowledge of the toxin amount contained in this mushroom type is invaluable in the treatment of cases involving poisoning. In this study, we analysed the toxin levels of the Galerina marginata growing in Turkey.Toxin analyses were carried out for dried G. marginata which were collected from the forests Kastamonu region of Turkey in 2015, as a whole. The alpha amanitin, beta amanitin, gamma amanitin, phalloidin and phallacidine analyses of the mushrooms were carried out using the RP-HPLC method. We found that the samples contain alpha amanitin (0.72 ±0.02 mg/g) and beta amanitin (0.56 ±0.03 mg/g), but G. marginata samples do not contain gamma amanitin, phalloidin and phallacidin. Alpha amanitin and beta amanitin concentrations were lower as compared to Amanita phalloides, but toxin content of G. marginata is dangerous and this species can cause lethal mushroom intoxication.