The authors evaluated whole blood filterability (VB) in 29 post-menopausal obese women with (n = 14) or without (n = 15) hypertension, and in 22 age matched women with normal body weight. After 3 months of a low-calorie (18 kcal/kg IBW) and moderately low-salt (max 6 g NaCl/day) diet, the obese subjects were restudied. In all women plasma fibrinogen values and various indices of metabolic status were evaluated before and after the diet and correlated to VB values. VB values and plasma fibrinogen concentrations were similar in normal controls and in women with simple obesity, whereas they were, respectively, significantly lower and higher in obese subjects with hypertension. Three months of diet significantly improved whole blood filterability and decreased fibrinogen levels in these patients. Before the diet a significant negative correlation was found between VB and plasma fibrinogen values in hypertensive obese patients. Metabolic parameters did not change in the different groups before and after the diet and did not correlate with VB values. The present study indicates that low-calorie, low-salt diet decreases plasma fibrinogen levels and improves whole blood filterability in elderly obese women with hypertension.