24-hour ph-metry of the oesophagus is a standard examination method in patients with reflux complaints. For objective evaluation of the record the following points are most important: 1. calibration of the instrument, 2. precise placement of the pH-probe, preferably under manometric control, 3. elimination of medication (inhibitors of proton pump, H-2 blockers, antacids, prokinetic preparations), 4. cooperation of the patient. A 24-hour record makes it possible to analyze in detail the type of reflux, and when using available software, also its quantity.