Spleen and liver represent target organs for involvement in patients with Hodgkin's disease and with non-Hodgkin's lymphomas. Although histological examination remains the most reliable method in diagnosing the presence of disease in these organs, particularly during the early phases, exploratory laparotomy and liver biopsy cannot be repeated, for practical purposes, on a regular basis. As the incidence of splenic and hepatic involvement continues to rise in the years following the initial diagnosis, we have found that liver and spleen scans performed in a serial manner are helpful in establishing the diagnosis during the follow-up period. By comparing the later studies to the earlier ones, interval changes as related to the size, contour, homogeneity and to the presence or absence of filling defects, become apparent. These changes, should they occur, are related, in our experience to the underlying lymphoma. Conversely, through serial scanning, improvement under treatment of a previously involved organ, is well demonstrated by this noninvasive technique. The limitations imposed by the resolving power of the imaging system must be taken into consideration when interpreting the results.