We studied hematological indexes (RBC, HB, HT, MCV), serum iron and serum ferritin values in 1784 randomly selected subjects aged 65 and over (725 males and 1059 females) divided into five age groups (65-69, 70-74, 75-79, 80-84, > or = 85 years). The subjects were classified as anemic and normochromic according to the criteria for a "geriatric" level of anemia (HB < or = 12 g/dL in both sexes) as well as "W.H.O." levels for anemia (HB < 13 g/dL in males and < 12 g/dL in females). Macrocytosis (MCV > 100 fl) and low serum ferritin level (< or = 12 ng/dL) were classified according to MCV and serum ferritin values. Mean HB values in males were 14.85 +/- 1.33; 14.82 +/- 1.40; 14.77 +/- 1.43; 14.59 +/- 1.47 and 13.83 +/- 1.13 in the five age groups (65-69, 70-74, 75-79, 80-84 and > or = 85 years) respectively; in females, they were 13.77 +/- 1.15; 13.75 +/- 1.27; 13.44 +/- 1.39; 13.44 +/- 1.52 and 13.34 +/- 1.61, respectively. There was a low frequency of anemia in the entire sample: 2.9% in males and 9.9% in females according to the "geriatric" level, and 9.4% in males and 8.8% in females according to the "W.H.O." level. There was a higher prevalence of macrocytosis in males (6.3%) than in females (3.3%). We conclude that red cell parameters tend to decrease in aging, and further investigations are needed that exclude persons with existing chronic conditions, and incorporate data on nutritional status.