I N 1 9 6 7, Northway and associates I described a form of chronic lung disease that they named bronchopulmonary dyplasia, basing their observations on newborn infants who received assisted ventilation for respiratory distress syndrome between 1962 and 1966. This disease appeared to progress through a series of four stages that were radiographically and pathologically distinct, terminating in chronic lung disease (Stage IV BPD). The radiographic appearance at each stage was characteristic, with Stage I appearing identical to uncomplicated RDS, Stage II being a period of pulmonary parenchymal opacity that cleared into a bubbly appearance (Stage III), which often ultimately became the rather distinctive pattern of chronic BPD (Stage IV).'-' Stage IV was defined chronologically as bubbly-appearing lungs persisting for 30 days or more. Subsequently this disease was observed by numerous investigators and described under a variety of names, including bronchopulmonary dysplasia, 3-1-~ pulmonary fibroplasia, 1~-1~ chronic pulmonary disease, TM respirator lung disease, ,~ and other descriptive terms? 9 -~ In most reports the diagnosis of BPD implies chronic disease, or Stage IV BPD. For most purposes, except when evolution of the condition is being discussed, this would appear to be a satisfactory convention. Since the initial descriptions of BPD, the disease appears to have changed, at least in certain of its radiographic manifestations. This article is a discussion of several recent observations, with particular emphasis on radiographic features and manifestations.