Lung tissue developmental abnormalities are seldom reported. According to the classification of Schneider (1900), which was amended by Boyden (1955), they include pulmonary agenesis, aplasia and hypoplasia. Due to the early onset of symptoms, lung agenesis and aplasia are usually detected soon after birth. Conversely, lung or lobar hypoplasia may remain clinically silent for a long time. A single case of left lower lobe hypoplasia is reported. A recurring and unrelenting septic fever was the presenting symptom, whilst the radiological picture showed a left lower lobe consolidation. On the surgical specimen gross pathology revealed a lobar hypoplasia. At a short-term follow-up (nine months) the patient shows good overall condition, being free from further complications.