Biological therapies have improved the prognosis of patients with inflammatory diseases. In adults, an increased risk of presenting infections has been reported, however, there are few pediatric studies. Objective: to describe the incidence of infections in pediatric patients using biological therapies. Patients and Method: Retrospective cohort study of pediatric patients with rheumatic diseases and inflammatory bowel diseases, treated with biological therapies, at the UC-Christus Health Network between 2007-2019. The number, type, and characteristics of mild and serious infections (hospitalization requirement, use of intravenous antimicrobials, association with mortality) were recorded. Descriptive statistics were used. Results: We included 128 patients diagnosed with juvenile idiopathic arthritis (89.8%), primary vasculitis (3.9%), and inflammatory bowel disease (3.1%). Adalimumab was used in 43.9%, Etanercept in 22.5%, and Tocilizumab in 16.8% of patients. 52.6% of patients reported an infection. The most common mild infections were upper respiratory tract infections (61.5%) and lower respiratory tract infections (10.6%). The most frequent severe infections were gastrointestinal infections (2.9%) and lower respiratory tract infections (2.3%). The incidence rate of mild infections was 119.7 (CI 106-128) per 100 person-years and the incidence rate of severe infections was 10.3 (CI 73.7-142.1) per 100 person-years. No cases of reactivation of tuberculosis or hepatitis B virus were observed. There were no hospitalizations in intensive care units, deaths, or need to suspend biological therapy due to infections. Conclusions: This study shows that biological therapies have a good safety profile, without reports of significant repercussions during infections, regardless of the underlying pathology.