The authors report a case of an 18-months old girl with primary tuberculosis, where erythema nodosum was the main symptom. She received BCG vaccination on the first day of life according to the Polish vaccination programme. Although there was no postvaccinal scar when she was 12 months old, she was not revaccinated. On hospitalisation, the tuberculin skin test was strongly positive. The girl had a confirmed contact with tuberculosis. On the base of the anamnestic data and the clinical course, Erythema nodosum of tuberculous etiology was diagnosed and treatment was introduced. Erythema nodosum is not specific for tuberculosis but in the differential diagnosis tuberculosis should be taken into consideration.