Nutritional epidemiology is a subdiscipline of epidemiology and provides specific knowledge to nutritional science. It provides data about the diet-disease relationships that is transformed by Public Health Nutrition into the practise of prevention. The specific contributions of nutritional epidemiology include dietary assessment, description of nutritional exposure and statistical modelling of the diet-disease relationship. In all these areas, substantial progress has been made over the last years and is described in this article. Dietary assessment is moving away from the food frequency questionnaire (FFQ) as main dietary assessment instrument in large-scale epidemiological studies towards the use of short-term quantitative instruments due to the potential of gross measurement errors. Web-based instruments for self-administration are therefore evaluated of being able to replace the costly interviewer conducted 24-h-recalls. Much interest is also directed towards the technique of taking and analysing photographs of all meals ingested, which might improve the dietary assessment in terms of precision. The description of nutritional exposure could greatly benefit from standardisation of the coding of foods across studies in order to improve comparability. For the investigations of bioactive substances as reflecting nutritional intake and status, the investigation of concentration measurements in body fluids as potential biomarkers will benefit from the new high-throughput technologies of mass spectrometry. Statistical modelling of the dietary data and the diet-disease relationships can refer to complex programmes that convert quantitative short-term measurements into habitual intakes of individuals and correct for the errors in the estimates of the diet-disease relationships by taking data from validation studies with biomarkers into account. For dietary data, substitution modelling should be preferred over simple adding modelling. More attention should also be put on the investigation of non-linear relationships. The increasing complexity of the conduct and analysis of nutritional epidemiological studies is calling for a distinct and advanced training programme for the young scientists moving into this area. This will also guarantee that in the future an increasing number of high-level manuscripts will show up in this and other journals in respect of nutritional epidemiological topics.