Infant apnea is a common problem that conveys significant burden to families and physicians. Its temporal relationship with gastroesophageal reflux (GER) is controversial. Aim: To establish whether infants with GER of different magnitude have a higher incidence of respiratory events than children without GER. Patients and Methods: 146 consecutive patients were evaluated with polisomnography (PSG) and with an esophageal pH probe. Those infants without GER episodes or with an esophageal pH below 4.0 in less than 5% of total sleep time were considered as physiologic GER (Group I), between 5-10% as mild GER (Group II), and over 10% as severe GER (Group III). These groups were evaluated for demographic and polysomnographic characteristics. Results: There were no differences in the demographic and global PSG characteristics neither in oxymetry, heart rate or electroencephalographic abnormalities. Group III infants had a higher percentage of active sleep compared to infants of Group I (p <0.05) and higher incidence of central pauses and apneas compared to infants of Group I (p <0.05). Conclusions: The presence of severe GER may modify the sleep pattern in infants, increasing the percentage of active sleep. The presence of central pauses and apneas in infants with severe GER suggest an association between the inmaturity of the respiratory centers and the adaptation of the anti-reflux mechanisms (Rev Méd Chile 2003; 131: 1143-50).