The approval of infliximab biosimilars Remsima™ and Inflectra™ (CT-P13) for patients with inflammatory bowel disease (IBD) is a promising step to reduce treatment costs. Since monitoring of Remicade™ serum trough levels and anti-Remicade™ immunogenicity hold an important significance in treatment modalities, no data about monitoring of drug serum trough levels or anti-drug antibody levels in IBD patients treated with Remsima™ or Inflectra™ are present to date. Therefore, in this study we applied a Remicade™-validated ELISA to determine drug serum levels of Remsima™ or Inflectra™. Serum concentrations were measured at identical levels compared to Remicade™ at multiple time points over 38 weeks, suggesting that the monitoring of serum trough levels is equally feasible for patients receiving Remsima™ or Inflectra™ and Remicade™. Additionally, anti-drug antibody levels were not significantly different in patients treated with Remsima™ or Inflectra™ compared to patients treated with Remicade™. To our knowledge this is the first real-life experience demonstrating the feasibility of drug monitoring in IBD patients treated with the infliximab biosimilars Remsima™ and Inflectra™.