We investigated the relationship between assessment of fatty acid intake by a 3-day food record and by capillary gas chromatography of erythrocyte phospholipid fatty acid. The study was performed in a sample of 244 men aged 45 to 66 years from the general population who were participating in the Monitoring of Cardiovascular Disease (MONICA)-Lille survey. The relationship between each nutrient and food item and erythrocyte phospholipid fatty acid was investigated by a regression model on proportion including each food item and nutrient as a dependent variable and percentage of fatty acid and covariables (nonalcoholic energy intake, age, alcohol intake, and smoking) as independent variables. Polyunsaturated fat and linoleic acid intake were positively correlated with linoleic acid content of erythrocytes (beta = 0.641 and 0.604, respectively, P < .001). Monounsaturated and saturated fat intake were correlated with oleic acid (beta = 0.375 and 0.373, respectively, P < .01). Fish intake correlated positively with docosahexaenoic acid (DHA) (beta = 0.383, P < .001) and negatively with arachidonic acid (beta = -0.509, P < .01). These data confirm, on a group level, a good relationship between assessment of polyunsaturated fat intake by a 3-day record and linoleic acid content of erythrocyte membranes. These data suggest that erythrocyte oleic acid content is a marker of both saturated and monounsaturated fat intake.