Asphyxia is a name given to different kinds of lesions that can produce similar histologic findings. Thus, because of the varied nature of the different kinds of lesions, as well as the incidence of similar qualitative histologic findings with different causes, the aim of this work was to study special kinds of injuries with particular subsequent impairment. These include some diagnostic problems of sudden death of natural causes, including aspiration, suffocation, drowning, and strangulation. Ranking was made of 167 victims based on the diagnosis as having: aspiration (n = 35), suffocation (n = 88), drowning (n = 27), and strangulation (n = 17). Stepwise discriminant analysis of the resulting data showed that lung necropsies from victims of these four events could be distinguished from one another. Statistical differences among the four groups were observed for eight morphologic parameters. A robust discriminant function permitted an adequate classification of the four groups of disease in 85.03% of the cases. Lung autopsies with congestion, septal hemorrhage, and foreign body showed a specificity of 100% for victims of aspiration, whereas ductal overinsufflation, interstitial edema, and bronchiolar constriction showed a specificity of 81.8% in victims of suffocation. Intraalveolar edema and dilatation of the alveolar spaces with secondary compression of the septal capillaries characterized drowning. Victims of strangulation showed a strong alveolar hemorrhage, with alveolar collapse and overinsufflation, associated with bronchiolar dilatation. It is concluded that semiquantitative analysis of lung autopsies might be a useful supplementary histologic criterion to support the diagnosis of asphyxia.