SummaryThirty patients with bronchial carcinoma, aged 45 or less, were identified as having attended this or other local chest clinics.In four cases the diagnosis was reached after four or more months of investigations. In two of these cases, pulmonary tuberculosis was incorrectly suspected to be responsible for the illness of the patient.Compared with the disease as it affects all age groups, there appeared to be no greater incidence of any particular presenting symptom. In the group of patients studied, there was an excess of small cell carcinoma compared with that expected.