Immunodeficiencies in clinical practice are relatively rare. The most common cause worldwide is HIV infection, both in children and adults. Among primary immunodeficiencies the most frequent one is IgA deficiency (IgAD), followed by CVID (common variable immunodeficiency). This paper describes a case report of a 14-year-old girl, raising the problem of CVID occurence in day-to-day medical practice. Typically the disease appears between the ages of 5-10 and 20-40. In 70-80% of patients the main manifestations are recurrent respiratory infections – pneumonia, bronchitis and sinusitis. Gastroenteritis and inflammatory bowel disease (IBD) also occur. Autoimmune diseases are present in 20% of patients, lymphadenopathy and splenomegaly can also be observed. Malignancy occurs 5 times more often when compared to the general population. Due to a diverse clinical manifestation, the diagnosis of CVID is usually greatly delayed, which may lead to serious complications such as bronchiectasis or pulmonary heart disease. The etiopathogenesis of CVID is not fully known. The main treatment consists of life-long immunoglobulin substitution in intravenous or subcutaneous form.