Objective: Invasive meningococcal infections have a clinical picture with a rapid onset and can lead to serious sequelae and death even in individuals who are treated early. The most common causes of related epidemics are serogroups A, B, C, W, Y, and X, and two different vaccines have been developed against serogroups A, C, W, and Y and serogroup B. The serogroup B-containing MenB-4C vaccine (Bexsero®) was licensed in Turkey in 2018 and is still being administered. In this study, the side effects of this vaccine in infants and children followed up in a tertiary pediatric clinic were questioned. Materials and Methods: In our study, the local and systemic side effects of the MenB-4C vaccine doses, which were administered between March 1, 2019, and March 1, 2022, at the Child Health Follow-up Outpatient Clinic of Gazi University Faculty of Medicine, were evaluated retrospectively. All infants and children aged 0-18 years who were vaccinated at this clinic on the specified dates (n = 102) were recruited, and a questionnaire was completed by calling their parents by telephone and questioning the side effects of the vaccine. Results: It was determined that a total of 224 doses of the MenB-4C vaccine were administered to 102 children over the three-year study period, Of these vaccines, 21.6% were administered during the year before the pandemic and 78.4% during the two years after the pandemic. According to the total number of doses, the rate of local and systemic side effects was 30.8% (n= 69). It was found that among the 69 doses with side effects, 42 (60.8%) were systemic (fever), and 27 (39.1%) were local (stiffness, redness, and pain at the injection site). Side effects were observed in 41.3% of the patients after the first dose of the vaccine, 23.3% after the second dose, and 25.9% after the third dose. Conclusion: In our study, no serious post-vaccine reactions, such as anaphylaxis and encephalopathy, were observed following vaccination with MenB-4C, and the most common side effects of this vaccine were fever and local pain, which were only transient and self-limiting, lasting only two to three days at most. Since the MenB-4C vaccine, which has been included in the vaccination schedule of most countries, is a strong tool to help prevent meningococcal infections, every parent presenting to a health institution should be informed by the physician about the necessity of this vaccine, and if possible, conjugated meningococcal vaccines containing not only serogroups A, C, W, and Y but also serogroup B should be added to the national vaccine scheme.