In a representative sample of 624 people, 65–84 years of age, from six regions of Croatia, Yugoslavia, proteinuria was investigated on the basis of certain medical characteristics. Established proteinuria was seen in 30.8% of females and 27.4% of males. Proteinuria was found to be significantly more common in people with urinary tract infections. Arterial hypertension with heart failure was more often seen in patients with than in patients without proteinuria, but the difference was not statistically significan