The results of a time study and the preliminary collection of morbidity data in rural prisons of Nicaragua prompted the medical delegate of the International Committee of the Red Cross (ICRC) to outline an assistance program based on three principles: (a) that the system be in line with the projects of the national health agencies; (b) that locally recruited and trained health workers become the primary directors of health care in prisons; and (c) that the medical delegate of the ICRC act as advisor to the local health workers.