['To evaluate the respiratory rate as an indicator of hypoxia in infants < 2 months of age.', 'Pediatric emergency unit of an urban teaching hospital.', '200 infants < 2 months, with symptom(s) of any acute illness.', 'Respiratory rate (by observation method), and oxygen saturation (SaO(2)) by means of a pulse oximeter were recorded at admission. Infants were categorised by presence or absence of hypoxia (SaO(2) </= 90%).', 'The respiratory rate was >/= 50/min in 120 (60%), >/= 60/min in 101 (50. 5%), and >/= 70/min in 58 (29%) infants. Hypoxia (SaO(2) </= 90%) was seen in 77 (38.5%) infants. Respiratory rate and SaO(2) showed a significant negative correlation (r = -0.39). Respiratory rate >/= 60/min predicted hypoxia with 80% sensitivity and 68% specificity.'] Is tachypnoea a good predictor of hypoxia in acutely ill infants under 2 months?