Pneumonia is one of the leading causes of death in children under 5 years worldwide. In resource-limited settings, WHO recommendations state that pneumonia can be presumptively diagnosed through the presence of cough and/or difficult breathing and a respiratory rate (RR) that is higher than age-specific cutoffs. As a new diagnostic aid the children's automated respiration monitor (ChARM) can automatically measure and classify RR in children under 5 years, but the effect of its chest attachment on the RR has not been studied. The aim of this study was to understand if misclassification of the true RR occurred by ChARM attachment. Two hundred eighty-seven children at a health center in South Ethiopia were screened for eligibility, with 188 children aged 2-59 months enrolled in the study. The RR was measured manually before and 1, 3, and 5 minutes after ChARM attachment. The proportion of children with fast or normal RR classification at baseline and the change between RR classifications over time were analyzed. Eight (4.9%; 95% CI 2.1, 9.4) of 163 children changed RR classification from normal to fast between the baseline RR count and the 1 minute RR count. Results from this study suggest that ChARM has a minor influence on the RR of children immediately after attachment, in most cases without clinical importance.