We present a patient with a necrotizing pneumonia due to Streptococcus pneumoniae. This complication often affects children and is relatively rare and unrecognized in adults. Its diagnosis is often difficult on chest-X-ray and need a chest computed tomography. No risk factors predisposing to necrosis are described in literature and its mortality is not different from pneumonia without necrosis. The serotype 3 is the most common type implicated in pneumococcal necrotizing pneumonia. Study of virulence factors of S. pneumoniae and various genetic polymorphisms of the host should allow a better understanding of this complication.