The present study investigated the effect of monounsaturated fatty acids (MUFA) on postprandial coagulation factor VII activity. Fifteen healthy male volunteers consumed three meals containing equal amounts (40g) of fat, but providing different proportions of MUFA (12,17 and 24% energy)in random order. Fasting and postprandial blood samples were drawn every hour for 9 h. The magnitude of the postprandial triacylglycerolaemic response and the postprandial plasma nonesterifled fatty acid (NEFA) concentrations were not significantly different following the three meals. Coagulation factor VII was activated during postprandial triacylglycerolaemia but the area under the curve of postprandial coagulation factor VII activity was not significantly different following the three meals. Regression analysis showed that fasting factor VII activity was the single mast important factor affecting postprandial factor VII activity, irrespective of plasma lipid concentrations and meal fat composition. Peak postprandial factor VII activity was attained significantly earlier following the high-MUFA meal compared with the low-MUFA meal (6·33 (SD 2·16) h, 3·60 (SD 1·81)h respectively; P = 0·016). Regression analysis showed that meal MUFA content was the primary determinant of time to peak postprandial factor VII activity. Although the magnitude of postprandial coagulation factor VII activity was not affected by meal MUFA content, peak postprandial factor VII activity occurred earlier and fasting activity levels were quickly restored following the high-MUFA meal. A short-lived increase in factor VII activity may be more beneficial than a prolonged thrombotic response.