TYPE: Case Report TOPIC: Chest Infections INTRODUCTION: Bronchopulmonary sequestration (BPS) is a rare congenital malformation of the lower respiratory tract; it consists of a nonfunctioning mass of lung tissue that is irrigated by an anomalous systemic artery. The association with Actinomyces superinfection has not been well established. CASE PRESENTATION: We present the case of a 35-year-old woman with a history of recurrent episodes of pneumonia. Based on radiological and histopathological examination, she was diagnosed with intralobar bronchopulmonary sequestration associated with Actinomyces infection. DISCUSSION: Pulmonary actinomycosis is a chronic, indolent and slowly progressive disease. The association of pulmonary actinomycosis with BPS has not been well established, and only one case has been reported in the literature so far; however, the identification of other microorganisms have been documented, the most prevalent being Aspergillus, Mycobacterium tuberculosis, nontuberculous mycobacteria, Pseudomonas and Nocardia. Most patients with BPS and superinfection, such as in our case, are asymptomatic and have carried the congenital anomaly for years without diagnosis, being identified incidentally during a routine physical examination or by recurrent episodes of lung infection. CONCLUSIONS: We present a rare case of pulmonary actinomycosis associated with BPS. These two entities have similar clinical characteristics, such as chronicity, the presence of multiple episodes of pneumonia and nonspecific radiological presentation. Therefore, clinical diagnosis is difficult and most likely the final diagnosis is made through histopathological examination, for Actinomyces are difficult to culture. There is a high frequency of infection in patients with BPS, and an accurate identification of the causative organism, including Actinomyces spp., should be achieved. DISCLOSURE: Nothing to declare. KEYWORD: Pulmonary actinomycosis