This paper reports on the incidence of advanced filariasis after basic elimination of bancroftian filariasis since 1983 in Shandong Province. Investigation was carried out in a population of 166,776 between 1984 and 1988 in 252 villages of Teng Xian and other 5 counties/cities, the erstwhile highly endemic areas. A total of 1,038 filariasis patients were found with an average incidence of 0.6%. Among them, 383 were with elephantiasis, 357 with chyluria and 298 with hydrocele. 902 cases (86.9%) who suffered the disease before the elimination of filariasis and 136 cases (13.1%) after it, 125 (91.9%) being chyluria cases. The oldest of the 1,038 cases was 86 years of age and the youngest, 6 years of age. The course of duration as 8-74 years in elephantiasis cases, 82.8% of them (317 cases) had previously lymphangitis and/or lymphadenitis. In the past three years 16.4% (52 cases) suffered from prolonged or intermittent acute lymphangitis and/or lymphadenitis. The results of this survey indicated that, after the basic elimination of filariasis in Shandong Province together with thorough clearance of infection source, elephantiasis and hydrocele persisted while new cases of chyluria continued to develop. Therefore, in such areas more emphasis should be put on the treatment of clinical patients. New patients should be surveyed and old patients be treated actively so as to reach the goal of eradicating filariasis.