The objective was to reveal and compare the adverse effects of infliximab, etanercept, adalimumab, ustekinumab and secukinumab, and determine possible risk factors. The follow-up files and computer-based records of patients with psoriasis were retrospectively screened between January 2007 and September 2019. The five biological agents were compared in terms of their adverse effects, and factors that might be related to these effects were explored. While there was no statistically significant difference between the agents in terms of the rate of serious adverse effects, when all the adverse effects were evaluated together, the highest rate was seen in the use of infliximab and the lowest in secukinumab (P= .001). The rates of adverse effects and related drug discontinuation were higher in the use of anti-TNF agents compared to interleukin inhibitors (P= .004 andP= .012, respectively). The agent with the highest drug discontinuation rate due to adverse effects was infliximab while the least discontinued agent was ustekinumab (P= .036). There were more side effects with anti-TNF than interleukin inhibitors, but the serious adverse effect rate was similar in both groups. The incidence of certain adverse effects increases depending on age, number of comorbidities, biological agent and its group, concomitant systemic therapy, and use of multiple agents.