Respiratory virus infections account for a significant proportion of acute admissions to the paediatric intensive care unit (PICU). Recent studies have shown that rhinoviruses (RV) are the most frequent virus detected in severe cases of acute respiratory illnesses (ARI) admitted to a PICU. The aim of this study was to determine the prevalence of different viruses, in particular RV species, in children with ARI admitted to a tertiary PICU. Nasopharyngeal aspirates (NPA) from 229 children admitted to PICU with an ARI were analysed. RV was the most common virus detected, being present in 94 (41.0%) of samples examined, followed by respiratory syncytial virus (RSV) which was identified in 50 (21.8%) samples. A subsection analysis of cases with residual sample available of sufficient quality to allow for RV species typing showed that overall, the percentage of PICU admissions for each RV species was 22.3% for RV-C, 17.5% for RV-A and 1.7% for RV-B. This study demonstrated that RV is the most frequent virus identified in children admitted to a tertiary PICU with an ARI and RV-C is the most common RV species detected. Importantly, in the children admitted to PICU with an ARI, RV-C was by itself as common a pathogen as RSV.