The variation of clumping factor in microfilaraemia among different age groups was observed in Pondicherry for 1981 and 1986. The clumping factor was minimum in the age group 0-5 yr and it was maximum in 16-20 yr group in 1981 and 21-25 yr in 1986. The variation in clumping factor resembled the changes in microfilaria (mf) rate. Multiple linear regression analysis showed that the multiple correlation between mf rate and the other parameters i.e., median microfilarial density (MFD50), clumping factor in human population, and, infection rate and infectivity rate in vector population was highly significant. The relationship between filariometric indices in human host and vector population may provide the basis on which a mathematical model on transmission of filariasis could be developed.