Increasingly, more neonatal respiratory extracorporeal membrane oxygenation (ECMO) patients in the Extracorporeal Life Support Organization (ELSO) registry have a primary diagnosis of Other. These patients, in addition to those with persistent pulmonary hypertension (PPHN), represent heterogeneous groups. This study aimed to reclassify Other and PPHN patients into modern categories to improve understanding of ECMO indications and outcomes. Data on neonatal respiratory ECMO cases from January 2017 to July 2021 from the ELSO registry were reviewed. Runs with primary and/or secondary diagnosis codes of Other or PPHN were evaluated for reclassification into 13 modern categories. Characteristics and outcomes were described. Three thousand two hundred thirty-four ECMO runs were included: 1,316 (41%) classified as Other, 251 (8%) as PPHN. Survival was 74% for the Other group. In total, we reclassified 573 of 1,567 (37%) runs, with 253 of 1,567 runs (16%) reclassified into a modern category. Ninety-one of 253 (36%) had hypoxic ischemic encephalopathy and 82 of 253 (32%) had pulmonary hypoplasia. Following reclassification, survival ranged from 0% for alveolar capillary dysplasia to 92% for aspiration of non-meconium fluid. Contemporary neonates placed on ECMO for respiratory failure are diverse. Important distinctions are lost in the catch-all categories of Other and PPHN. Improvements in data entry and categorization are needed to effectively use the ELSO database.