Bronchopulmonary dysplasia (BPD) remains as the most frequent chronic lung disease seen among babies with very low birth weight, contributing to their morbidity and mortality. An increase in the survival of very immature babies due to improvement in pre and post natal care, has resulted in an increase in the number of newborns with BDP, although there have been no changes in the actual incidence of the disease. Objective: Lo describe the evolution of DBP in recent decades, the current definition, and to describe and analyze the risk factors involved in the pathogenesis of this disease. Until a few years ago, the terms BPD and chronic lung disease were used as synonyms. After the workshop sponsored by the National Institute of Health in the United States in 2001, it was recommended that the term BPD be used to describe the pulmonary sequelae of immature babies. Classic severe BPD, as described by Northway et al over forty years ago, has evolved into milder forms of chronic pulmonary damage, the so-called "new BPD", characterized by impairment of alveolarización and vascularization of the immature lung in response to multiple injuries. BPD is a multifactorial disease where major risk factors are related to pulmonary immaturity, hyperoxia, baro/volutrauma, as well as inflamation and infection. Genetic susceptibility has recently been shown to be another important risk factor. Conclusion: Bronchopulmonary Dysplasia continues to be the most frequent sequelae affecting low birth weight infants. In the past four decades, the disease has been better defined, and new pathogenetic risk factors have been established.