Within the EPIC study (European Prospective Investigation into Cancer and Nutrition) a calibration approach is applied to compare dietary data obtained by food frequency questionnaires from 9 European countries. A software for 24-h recalls was developed as the calibration instrument by the International Agency for Research on Cancer (IARC) in collaboration with all national EPIC centers. This computer program, called EPIC-SOFT, is an interview-based dietary assessment instrument that allows one to obtain a very detailed description and quantification of foods, recipes, and supplements consumed in the course of the preceding day. Probing questions and entering consumed foods in chronological order support the respondent's memory. The standardized structure prescribes--on the food group level--possibilities of description and quantification of food items to choose from. Quantification of consumed foods is supported by the EPIC-SOFT picture book that comprises colored photographs of foods in different portion sizes. The software provides an automatic coding of food items and recipe ingredients as well as calculation of nutrient intake. EPIC-SOFT is characterized by the obtained standardization of dietary data within Europe, a large number of available foods and recipes, and a very detailed description of consumed foods. Currently, EPIC-SOFT is one of the few dietary instruments providing comparable nutritional data within Europe.