Febrile neutropenia (FN) is one of the most common complications in pediatric oncology patients. It has a complex etiologic nature, which in the majority of cases remains unclear. Intervention often follows empirical treatment protocols, mainly using broad-spectrum antibiotics. To evaluate potential viral etiologic agents, this study applied viral metagenomics to paired plasma and oropharyngeal samples obtained from pediatric patients with oncological diseases diagnosed with FN. Metagenomic sequencing was performed on 15 pediatric patients with oncological diseases and FN at the outpatient clinic of Pediatric Oncology at the University Hospital of the Faculty of Medicine of Ribeirão Preto, University of São Paulo. As a control group, we included 15 pediatric patients with oncological diseases in remission or undergoing treatment. Clinically relevant viruses identified by metagenomics in FN patients predominantly included herpesviruses and viruses found in the respiratory tract, like adenoviruses. Direct molecular confirmation was performed on all of them. Anelloviruses, represented by various genera and species in all groups, were also highly prevalent. The data obtained in this study show that viruses might also have possible implications for the etiology of FN. However, due to the complex nature of this disease, more studies are necessary to evaluate their causal relationship. The results obtained in our study may serve to improve patient treatment and ensure adequate management.