Introduction Myocarditis, inflammation of the heart muscle, can be caused by infections, autoimmune disease or exposure to toxins. The major cause of myocarditis in the paediatric population is viral infection, including coxsackievirus B3, adenovirus, herpesvirus, parvovirus, influenza A and B, and hepatitis. Here, we report the detection of rhinovirus C in a boy with a clinical presentation of myocarditis, suggesting a possible causative role of this virus in this case. Case presentation A previously well 4.5-year-old boy presented with increasing breathlessness for a week prior to admission. He also had upper respiratory tract infection a few days before the event. An echocardiogram revealed severe left ventricle (LV) systolic dysfunction with dilation of the LV. RNA was extracted from serum and two nasal swabs, and tested with conventional PCR at the family level for viruses including enterovirus, dengue, chikungunya, influenza, herpesvirus, paramyxovirus and coronavirus. Further characterization of the enterovirus group was carried out using PCR with primers targeting the VP4/VP2 gene, followed by sequencing. Molecular tests showed the presence of rhinovirus C genetic material in both serum and swab samples. Phylogenetic analysis of the VP4/VP2 region showed 96-97 % similarity with the closest strain isolated in Ulaanbaatar (Mongolia) and Japan in 2012. Conclusion We report the possible association of rhinovirus C and myocarditis in a child presenting with acute onset of dilated cardiomyopathy.