We have developed a robotic tele-ultrasound system (OTELO) that allows an expert to examine a distant patient by ultrasound. At the expert station, a sonographer controls a virtual probe. Movements are reproduced at the patient station, which may be several kilometres away, on a real probe held by a lightweight robot, which is positioned on the patient by a paramedic. Two medical teams tested the tele-ultrasound system at two different hospitals on a total of 52 patients. Except for some difficulties caused by particular conditions, the diagnosis obtained with the remote scanning system agreed in at least 80% of the cases with the diagnosis made by conventional scanning. The results demonstrate the feasibility and efficiency of the device.