Otolaryngology is one of the surgical specialities employing high-powered instruments and this study was designed in order to establish whether sound levels at work conform to HSE guidelines. No study to date has measured intra-operative noise levels in ENT operation theatres. A prospective observational study was therefore performed. Sound levels were measured during the use of bone drills for mastoid surgery and microdebriders for endoscopic sinus surgery. A SLM/IS Acos Class I sound level meter calibrated to BS 1259 was employed. A spectrum analysis of drill-generated noise was measured using a calibrated B and K precision sound level meter. Sound levels emitted varied as follows: Large burrs- 72.4 dB (A), medium size; 71.2 dB (A), small sized burrs- 68.8 dB (A) (all values for cutting burrs) and 60.8 dB (A) for diamond burs. With microdebriders, the average sound level was 60.1 dBA. Spectrum analysis revealed that the maximum intensity was at 3.15 kHz, followed by 4 kHz, while the least sound was produced at 40 kHz and 31.5 kHz. Essentially sound produced by drills was between 1.6 kHz and 6.3 kHz. Powered instruments used in ENT surgery are safe and pose no occupational hazard.