The key elements of programmes for monitoring food contamination are reviewed in relation to their purposes, scope and priorities. Attention is drawn to the requirements and quality assurance of procedures for sampling and analysis, and methods of handling and processing analytical surveillance data. The benefits to be derived from national monitoring programmes are improved food safety, warning of problems of contamination, provision of intake data for evaluation of health hazards, better management and use of natural resources, supply of data on environmental pollution and reliable information on food safety for the public, and provision of a means of checking the effectiveness of regulatory mechanisms and planning technological developments.