Background. Obstructive sleep apnoea is commonly aggravated by the supine body position. The impact of body position on the severity of mixed and central sleep apnoeas is understudied. Objectives. To evaluate the impact of body position on obstructive, mixed and central apnoea indices in subjects presenting with this triform of sleep apnoea during a single polysomnogram. Methods. We retrospectively analysed 26 polysomnograms where obstructive, mixed and central apnoeas each occurred at a rate >5/hr. Comparisons between lateral and supine body positions were made for obstructive apnoea index (OAI), mixed apnoea index (MAI), central apnoea index (CAI), apnoea-hypopnoea index (AHI) and obstructive apnoea-hypopnoea index (OAHI). Results. Mean (SD) apnoea indices were significantly lower in lateral v. supine positions, respectively: