The omentum, a rich source for trophic and angiogenic factors, was explored as a potential intermediate transplant site to facilitate long-term survival of chromaffin tissue. Autologous rat adrenal medullas were grafted into omental pockets. All grafts became densely vascularized. The grafted chromaffin tissue exhibited strong immunoreactivities for tyrosine hydroxylase, synaptophysin and chromogranin A throughout the observation period of 16 weeks. The expression of these markers implies that grafted chromaffin cells retained the key enzyme for catecholamine biosynthesis and the organelles required for catecholamine secretion. Moreover, intermediate transplant of chromaffin tissue to the omentum could provide a favourable conditioning microenvironment thus augmenting the potential for survival of functional chromaffin tissue.