In the last twenty years many large epidemiological studies have made efforts to collect material for biological specimen banks. These banks contain samples collected for short or long-term cryopreservation at low (e.g. -70 degrees C) or very low (-192 degrees C). This report describes general guidelines and methodological issues to take into consideration in designing and developing a biological specimen bank and is based on experience of three large scale studies. The author describes quality, quantity, methods to collect samples, and condition of cryopreservation that ensure both testing of scientific hypotheses and integrity of the stored samples. Feasibility and long-term storage effect studies should always be part of the design and the basic organization of a biological specimen bank. All operative choices a researcher makes in setting up a biological specimen bank have a direct impact on the future use of the biological samples and should be carefully considered.