UNLABELLED: We aimed to characterize encephalitis, myositis, and myocarditis, in hospitalized children during the 2023 - 2024 dengue epidemic in Argentina. This case series included patients younger than 16 years with laboratory-confirmed dengue hospitalized for atypical manifestations across ten centers from Argentina between July 2023 and July 2024. Data was collected via a REDCap form version 12.4.1 (Vanderbilt University). Statistical analysis was performed by RStudio. We enrolled 47 patients; median age was 7 years [IQR 2 - 11], 64% were male, and 62% had no underlying conditions. Encephalitis was the most frequent clinical manifestation (60%), followed by myositis (38%) and myocarditis (4%). One patient had concurrent myositis and myocarditis. DENV-2 and DENV-1 were the identified serotypes. The 32% of patients required PICU admission, primarily those with encephalitis (n = 13) and myocarditis (n = 2). Thirteen patients required inotropic support and mechanical ventilation. Empirical antibiotics were administered in 32% of cases; no bacterial co-infections were identified. Median hospital stay was 5 days [IQR 3 - 8]. In 4 patients residual sequelae at discharge (persistent muscle weakness, myocardial fibrosis, and seizures) were detected. No deaths occurred. Encephalitis, myositis, and myocarditis are uncommon but clinically significant dengue complications in children. CONCLUSION:  Encephalitis and myositis were the most frequent atypical manifestations of dengue in this multicenter registry. Encephalitis and myocarditis were associated with a higher rate of PICU admission. WHAT IS KNOWN: • Atypical dengue manifestations in children such as encephalitis, myocarditis, and myositis, affect males predominantly, and may be associated with greater severity. • These clinical pictures are frequent in endemic countries, with a high burden of cases annually. WHAT IS NEW: • Argentina has become an endemic country with a cyclic epidemic pattern. • This was the largest epidemic in the country with a high burden of cases of dengue. • The cases had mild evolution in this new endemic scenario, with adequate clinical support.