To assess some of the socio-cultural reasons hindering psychiatric follow-up studies in Iran, 107 depressed patients were followed up for a period of about 3 years. Home visits were made, following two successive letters to which only five patients replied. Forty-five patients were interviewed, nine had moved, four refused interviewing, two were dead and the addresses or names of 47 were wrong. Wrong names and addresses, and behind them the illiteracy, change of address and the stigma of mental illness were the major causes of untraceability; the patients are inaccurate in giving their address and they may use one or another of their several names, surnames and nicknames. To make follow-up studies feasible, and as the patients and their relatives are the main sources of information, a more efficient registration system should be developed, with due respect to the characteristics of the population, to ensure having complete and correct names and addresses and to ensure patients' continual contact with the office.