The authors report a case of a lung abscess caused by Nocardia sp. in a previously healthy adolescent. A 17-year-old young man presented with tonsillitis that did not respond to β-lactamic antibiotic, dyspnoea and thoracic pain. The X-ray revealed a cavitation in the right pulmonary upper lobe. He was admitted and completed a 14-day empirical antimicrobial therapy for a pulmonar abscess, although no clinical recovery was observed. He then underwent pulmonary biopsy of the lesion and PCR analysis of the collected pulmonary tissue, which revealed the presence of Nocardia. This case emphasises the importance of considering nocardiosis in the differential diagnosis of a lung abscess, particularly if no response to empirical therapy is obtained.