Follicular fluid influxed into the oviduct during ovulation may affect movement of sperm for fertilization Thus, in this study, the effect of follicular fluid, obtained from follicles of l0mm in diameter, on number and quality of sperm recovered by swim-up separation was investigated and sperm-movement stimulating components extracted from follicular fluid with methanol and isooctane were separated by gel filtration with Sepadex G-1O, G-25 and G-1OO gels, and were isolated by electrophoresis with SDS-PAGE mini gel. The results obtained were as follows; 1. Diluted follicular fluid stimulated sperm movement. 2. Sperm-movement stimulating factors were in methanol extract. 3. Sperm-movement stimulating effect of methanol extract appeared in fraction I among fractions recovered after gel filtration. And the fraction I contained proteins indicating 4 major bands as about 47, 43, 25 and 14 kilodaldons and 5 minor bands as about 67, 58, 23, 22 and 21 kilodaldons. 4. The fraction I recovered from G-100 gel showed significantly low percentage of motile sperm and had no protein indicating the band of 67 kilodaldons among the minor bands.