Morbidly obese patients have a high prevalence of known and unknown cardiopulmonary diseases. The aim of this study was to assess the value of cardiopulmonary tests routinely performed before bariatric surgery.The population studied included 67 women and 10 men, aged 39 +/- 10 years, with a body mass index of 43 +/- 4 kg/m2. All patients, candidates for laparoscopic gastric banding, underwent after clinical evaluation: resting electrocardiography (ECG), Doppler-echocardiography, exercise stress testing, Epworth Sleepness Scale, and polysomnography, spirometry, blood gases, and chest x-ray.The ECG demonstrated conduction or ST-T wave abnormalities in 48 patients (62%). Prolongation of the QT interval10% was found in 13 patients (17%). Stress tests were negative in 56 patients (73%) and were not interpretable in the remaining 21 patients (27%). Doppler-echocardiography showed hypertrophy of the left ventricular posterior wall in 47 patients (61%) without any consequences on perioperative management. Polysomnography showed an obstructive sleep apnea-hypopnea syndrome (OSAHS) in 31 patients (40%), leading to preoperative continuous positive airway pressure (CPAP) treatment in 17 patients (22%). Nevertheless, the Epworth Sleepness Scale was pathological in only 17 patients (22%). Ten patients (13%) presented minor chest x-ray alterations. Spirometry demonstrated an obstructive respiratory syndrome in 13 patients (17%) and a restrictive syndrome in five patients (6%). Hypoxemia80 mmHg was observed in 21 patients (27%) and hypercapnia45 mmHg in six patients (8%), without any consequences on the management of the perioperative period.We recommend the preoperative assessment by clinical evaluation, ECG, and polysomnography. For patients with cardiac or pulmonary histories and/or ECG abnormalities, we recommend echocardiography, spirometry, and blood gases.