Abstract: In 18 villages with schistosomiasis basically eradicated for 5 to 15 years and with proportions of cured patients ranged from 2.3% to 63.9%, a comparative study was performed between COP and IHA to see if they could be of use in the evaluation of disease control. A total number of 4 361 residents were examined and the results showed that in these villages with the disease controlled for more than 10 years the reaction rate and the mean oircumoval precipitin rate of the cohorts with past history were all similar to those without previous history of schistosomiasis, and those of the patients cured for more than 10 years were as low as those of the villagers without any history of the disease. However, the GMRT as well as the reaction rates of IHA in both cohorts in these villages differed significantly, and so did the 2 patient groups cured for more or less than 10 years.A relationship of multiple regression was presented among the mean circumoval precipitin rate of COP, the number of years for a successful basic eradication of thedisease (X1) and the rate of population with past history of schistosomiasis (x2) inthe given areas. The equation of the regression is Y=- 0.0198X1+ 0.0030x2+0.2744.This equation can be used to express the range of eradication of the disease after COP survey in an unknown area.