Regurgitation is a common manifestation in infants below the age of 1 year and a frequent cause of visits to general practitioners and pediatricians. Accurate diagnosis of this condition requires a good choice of pH monitoring equipment and optimal technique when performing this procedure. The present article is a consensus statement of the Working Group on Gastroesophageal Reflux of the Spanish Society of Pediatric Gastroenterology, Hepatology and Nutrition (SSPGHN) and reflects the conclusions reached in the VII Congress of the SSPGHN (Vigo, 2000). In general, esophageal pH monitoring is indicated in the following situations: (i) when symptoms of gastroesophageal reflux are present and evolution is not favorable, despite appropriate treatment; (ii) when trying to determine the relationship between gastroesophageal reflux and non-digestive symptoms and (iii) when evaluating the results of treatment, whether medical or surgical.