Rationale: The prevalence of obstructive sleep apnoea (OSA) increases with age; in 50-60 year olds it is 31%, compared to 17% in 30-40 year olds(1). The mechanism for the age-related increase in OSA is unclear. Risk factors could include an enlarged tongue, soft palate and adipose deposits lateral to the pharynx(2). The aim of this study was to test the hypothesis that aging per se was associated with a reduction in the upper airway morphology in older (>60 years) males with no co-morbidity, compared to younger (<40 years) healthy males. Methods: A cross-sectional, observational study was carried out on 16 healthy younger males (mean + sd, age: 28.4 ± 4.2 years) and 10 healthy older males (age: 67.2 ± 5.2 years). Groups were matched for body mass index (Younger: 27.0 ±4.3 vs Older: 27.3 ± 1.8 kg/m2; p=0.8) and neck circumference (Younger: 39.9 ± 2.2 vs Older: 40.3 ±1.4 cm; p=0.5). All participants had an apnoea-hypopnoea index (AHI) <5 events/hour and were not subjectively sleepy. Mean pharyngeal cross-sectional area (APmean), pharyngeal volume (Pvolume), glottis cross-sectional area (AG) and pharyngeal length (Plength) were measured using acoustic reflection between the mouth and epiglottis, over 40 breaths. Measurements were made in the evening (17:00-20:00) while awake, in a supine posture after 5 minutes of lying still and breathing quietly. Differences between groups were tested for significance using 1-tailed independent samples t-tests (p=0.05). Results: Pharyngeal dimensions are shown in Figure 1. AG and APmean were greater in the older group (p=0.002 and p=0.03 respectively). Pvolume also appeared to be greater in the older group but this failed to reach significance (p=0.06). Plength was not different between groups (p=0.4). Summary: The pharyngeal calibre of the older healthy males was significantly greater than younger healthy males. These findings do not support our hypothesis that aging is associated with a reduction in the calibre of the upper airway. We speculate that the larger pharynx in the older people was protective of OSA.