The incidence and the prevalence of aspiration pneumonia (AP) in the community is poorly defined. It increases in direct relation with age and underlying diseases. The pathogenesis of AP presumes the contribution of risk factors that alter swallowing funtion and predispose the orofaringe and gastric region to bacterial colonization. The microbial etiology of AP involves Staphylococcus aureus, Haemophilus influenzae and Streptococcus pneumoniae for community-acquired aspiration pneumonia and Gram-negative aerobic bacilli in nosocomial pneumonia. It is worth bearing in mind the relative unimportance of anaerobic bacterias in AP. When we choose the empirical antibiotic treatmentant we have to consider some pathogens identified in orofaríngea flora. Empirical treatment with antianaerobics should only be used in certain patients. Videofluoroscopic swallowing studies should be used to determine the nature and extent of any swallow disorder and to rule out silent aspiration. Assessment of swallowing disorders is cost-effective and results in a significant reduction in overall morbidity and mortality.