The prognosis and clinical findings related to prognosis were examined in 300 patients with congestive heart failure in a prospective study. The diagnosis was based on case history data (NYHA class II or III), depressed ejection fraction (< or = 40%) and/or increased cardiothoracic ratio (> or = 50%). Forty-eight (16%) patients died within 1 year after the entry examination. Non-invasive baseline parameters of survivors and non-survivors were compared. All necessary medication was allowed. At the entry of the study three parameters independently predicted an increased mortality on a high significance level (P < 0.01): cardiothoracic ratio, signs of lung congestion on the chest X-ray (four grade classification), and plasma urea level; other three parameters did so on a lower significance level (P < 0.05): plasma natrium, creatinine value and endsystolic volume. Other parameters such as age, ejection fraction, NYHA class or exercise tolerance duration were not statistically different in survivors and non-survivors. Our modification (a four grade classification) of the signs of lung changes on the chest X-ray enables a more accurate determination of the prognosis in patients with chronic heart failure.