Abstract: The membrane filtration technique has been used widely in the evaluation of effect of control and survey of filariasis. The presem study was made to explore an optimum number of mixed peripheral blood samples and a mathematical model of work load for this method in surveying filariasis. By analysing the correlation between the microfilare-mia rate and the optimum number of mixed peripheral blood samples and applying the heory of Binomial Distribution or Poisson Distribution, the authors reckoned a table for estimating the number of filariasis cases in villages with different microfilarial rates and different population as well as the optimum number of mixed peripheral blood samples.