Despite the use of "oxygen dependence at 36 weeks postmenstrual age" to define bronchopulmonary dysplasia, criteria for the use of oxygen is rarely defined. We surveyed members of the Vermont Oxford Network regarding their criteria. Pulse oximetry saturation thresholds varied widely from <84% to <96%, with only 41% of the respondents using the same criteria (<90%). This lack of uniformity in the use of oxygen casts doubt on conclusions derived from multicenter trials that use oxygen dependence at 36 weeks postmenstrual age as an outcome.