To investigate the risk factors and characteristics of obstructive sleep apnea records were reviewed retrospectively of 88 patients at a European center (UK) during January-October 2005 and 198 patients at a Middle Eastern center (Qatar) from April 2002-April 2005. A greater percentage (83%) in the UK group had OSA (RDI-5 events/hr) compared to 55% in Qatar (p < 0.05). In both groups OSA was diagnosed more in males. Declared alcohol intake, smoking, insomnia, witnessed apnea and nocturia were associated significantly with OSA in the UK group (p < 0.05). BMI was significantly higher in the Qatar group (mean 34 kg/ m2) than the UK group (mean 31.2 kg/m2) (p < 0.05). The mean age, mean Epworth sleepiness score and associated vascular conditions were similar in both groups and hypertension was relatively common in both groups. It is concluded that obstructive sleep apnea in the West (UK) and the Middle East (Qatar) has similar risks and associations. That in the UK might arise from higher alcohol consumption and smoking of tobacco while mean BMI in Qatar is high although the exact contribution of these factors needs further evaluation.