The incidence of small nephromas of less than four centimeters in size has increased over the past decades with the increasing number of imaging studies. The majority of these tumors are kidney cancers exhibiting large variation in their aggressiveness. Systematic surgical treatment of these tumors results in more harm than benefit especially for elderly patients having associated diseases. Biopsy procedures from tumors by current methods are safe. The challenge of active surveillance is to identify those nephromas that are no longer safely monitored before the cancer is beyond the reach of curative treatment.