Summary. This article describes a study of the relationship between diet and smoking in a group of 821 Norwegian pregnant women. The study is part of a multi-centre project, examining risk factors for intrauterine growth retardation. Two 3-day dietary records were collected during the 17th and 33rd week of pregnancy. Information on smoking habits and other relevant parameters were collected through an extensive questionnaire. The results showed that the smokers consumed significantly less than the non-smokers of bread, cakes and cookies, vegetables, fruits and berries, cheese, yoghurt, low fat milk, juice and tea. The smokers also consumed significantly more meat, margarine, whole milk, soft drinks and coffee than the non-smokers on both occasions. The diet of the smokers contained significantly less protein, carbohydrate, dietary fibre, thiamin, riboflavin, vitamin C, calcium and iron as compared with the non-smokers. Fat contributed significantly more to the energy content of the diet of the smokers and it is concluded that their diet was less nutritious than that of the non-smokers throughout pregnancy.