The diffusion of New Psychoactive Substances (NPS) in the illicit drug market is a worldwide problem. The aim of the study is to describe the qualitative distribution of drugs of abuse in seized materials confiscated in the Italian territory over the last two years. Between 2013 and 2015 162 seizures of substances purchased through the Internet and confiscated by police authorities were analyzed: 35 seizures (22%) were crystals of 3-methylmethcathinone (3-MMC). Although 3-MMC is subject to the relevant legislation in Italy, it is not controlled in other countries such as the Netherlands, from which the shipments originated. 33 seizures (20%) were crystals of 4-methylethcathinone (4-MEC), 19 seizures (12%) were powders containing methylenedi...