Invasive fungal infections (IFI) are life-threatening complications of intensive chemotherapy treatment, with the incidence in pediatric patients ranging from 2% to 21%. In this article, we describe our 5-year experience of IFI in pediatric oncology patients and its clinical manifestations with radiological findings, treatment and outcome. A retrospective and descriptive survey of IFI in children with hematologic neoplasms was conducted at the Department of Oncology and Hematology, Zagreb Children’s Hospital. Medical charts of children 0-17 years of age, of both sexes, treated for leukemias and lymphomas from January 2016 to December 2020 were reviewed. In a 5-year period, 60 patients were treated for hematologic malignancy, acute lymphoblastic leukemia (ALL) being the most prevalent diagnosis. IFI was verified in 9 (15%) children, predominantly in patients with ALL (75%). The specific causative agent was detected in one child, whereas other infections were classified as probable pulmonary aspergillosis. All the patients received standard prophylaxis with fluconazole and treatment with liposomal amphotericin B and voriconazole. The majority of our patients achieved recovery. IFI prevention, diagnosis and treatment remain a challenge. Uniform prophylaxis and therapy protocols, as well as environmental control are of vital importance for the development of better strategies in the prevention, early detection and treatment of IFI in pediatric hematology patients.