Objective To develop and test a book of photographs of commonly eaten foods to be used as a visual aid in the description of portion sizes in a large cross-sectional study on the health profile of Africans in transition (THUSA – Transition, Health and Urbanization in South Africa). Setting Clinics in the North West Province of South Africa. Participants One hundred and sixty-nine adult African volunteers Design Data on commonly eaten foods, preparation methods, recipes and portion sizes were collected in a pilot study. Colour photographs, taken of foods prepared by the researchers and measured into three or four portion sizes, were enlarged and put together in a book. The food portion photograph book (FPPB) was tested by presenting subjects with a portion of real food and asking them to estimate the portion size by matching it with one of the portion photographs. Main results Of 2959 portions tested, 68% were accurately estimated (estimated weight within 10% of actual weight). Clearly defined solid foods were better estimated than foods that had an amorphous appearance. Accuracy of estimation was not affected by gender, age or education. Conclusion The FPPB was accepted as a useful and convenient visual aid to estimate portion sizes in the cross-sectional dietary intake study.