AIM: Down syndrome (DS) involves an extra chromosome 21 and tongue hypotonicity. This study examined reproducibility of tongue pressure measurement (TPM) in DS patients. METHODS: Thirty patients with DS (13 females) who were able to complete three measurements underwent a tongue pressure test (TPT). Reproducibility was evaluated using intraindividual standard deviation (SD) and coefficient of variation (CV). Patients were divided into two groups based on developmental age (DA): DA ≥ 4 years (over-4 DA) and DA <
4 years (under-4 DA). RESULTS: Thirty DS patients with a mean age of 33.0 ± 11.7 years and mean DA of 3.8 ± 1.2 years were analyzed. Median tongue pressure was 17.6 kPa, SD was 2.0 kPa, and CV was 11.9. Eleven patients were in the under-4 DA group, and 19 were in the over-4 DA group. Significant differences in speech presence and CV values were observed between the groups (p = 0.002, 0.043). CONCLUSIONS: The reproducibility of the TPT in DS patients with a DA ≥ 4 years is comparable to that in normal subjects.