Background:Psoriasis is a chronic, immune-mediated inflammatory disease estimated approximately in 2% of the European population. Drug abuse is reported in 3-5% of the global population. Main observation:We present a 41-year-old, cocaine-addicted patient male with severe plaque-type psoriasis treated successfully with ustekinumab. The patient received ustekinumab at a dose of 45 mg subcutaneously at weeks 0, 4 and 16 and achieved PASI 75 at week 18.Conclusions:Although several drug-abusers experience psoriasis, literature is very poor regarding the outcome of systemic treatment in those patients. In our patient no adverse effects were seen during the administration period of ustekinumab and no interactions between cocaine and ustekinumab were noticed. Nevertheless, more individuals and further studies are needed to establish the efficacy and safety of ustekinumab in the treatment of psoriasis in drug-abusers.