ObjectiveTo determine the effectiveness and safety of infliximab and etanercept biosimilar drugs in patients diagnosed with rheumatoid arthritis, ankylosing spondylitis, ulcerative colitis, and psoriasis in a specialized institution in Colombia, between 2015 and 2019. MethodsA retrospective study in patients treated with infliximab and etanercept biosimilar drugs treated in an institution specializing in the management of rheumatological diseases, to verify the clinimetric indicators of effectiveness and reports of adverse drug reactions. Clinical, sociodemographic, and pharmacological variables were identified over 5 years of follow-up. Results207 patients were identified with a mean age of 48.7 ± 15.1 years, 61.4% were women. Of the patients, 58% (n = 120) used infliximab and 42% (n = 87) etanercept. It was found that 46 (22.2%) patients had adverse drug reactions. At the end of the observation period, 61.6% (n = 72) of the patients with RA had achieved control of the disease (mild activity or remission), and 57.9% (n = 117) had problems with access to and persistence with therapy. ConclusionIn a group of patients treated in Colombia, the biosimilars of infliximab and etanercept showed proportions of effectiveness and safety comparable to the reference drugs, but lack of adherence to treatment was quite common.