Background: Invasive fungal disease (IFD) is a common and serious consequence of leukaemia in children and the incidence of these infections increased due to chemotherapy. We present the epidemiology of IFD in a cohort of children with leukaemia from a tertiary reference institution in Oman. Methods: A retrospective study of IFDs in pediatric patients with newly diagnosed or relapsed leukemia was conducted at the Royal Hospital in Muscat, Oman. From 2010 to 2017, IFD episodes in children with leukemia were evaluated retrospectively, taking into account age, gender, type of leukaemia, chemotherapy regimen, IFD detection phase, neutropenia, prophylaxis, diagnostic method, and treatment. Results: Between 2010 and 2017, 198 children with leukemia were admitted and treated at Royal Hospital. In retrospect, the IFI were defined as probable and proven in 53 % (17 patients) and 47% (15 patients) of the attacks. At 1.1:1, the male-to-female ratio was roughly equal. According to chest computed tomography (CT) scans, 65.6% of patients had radiological features of fungal infections. Positive fungal cultures were found in three patients’ bronchoalveolar lavage (BAL), 37.5% of whom had positive blood cultures, and 3% of whom had positive urine cultures. In 3 patients, invasive aspergillosis caused pulmonary IFD, accounting for 9.3% of all infection sites. Candidaemia was found in 28% of IFD patients. The most common organism was Candida tropicalis (15.6%), followed by Candida prapsilosis (6.25%). Conclusion: In children with leukemia, invasive fungal infection is common and serious. Despite aggressive treatment, mortality among these high-risk patients remains high.