Ovulation induction was done with 3 different regimens as clomid combined with HMG, HMG only, and FSH combined with HMG in 28 menstrual cycles for IVF-ET and GIFT program. The appearance of endogenous LH surge, estradiol plateau, atypical LH surge, and time from initiation to peak of LH surge in serum and urine were observed and compared in 3 groups. 1. The estradiol concentration of serum LH surge day was similar in three groups but 1st group (Clomiphene Citrate+Sequential HMG) was slightly higher at $1924.0{pm}865.1;pg/ml$. In regards to the existence of serum estradiol plateau, 3rd group (FSH+Sequential HMG) was highest at 60%, and 1st group and 2nd group (HMG only) were similar at 33% and 44% respectively. 2. The number of ovarian of ovarian follicle which was more than 18mm in diameter was $4.1{pm}2.0$, $4.2{pm}2.1$ respectibely for 2nd group and 3rd group. Although the numbers were slightly higher thean 1st group for each ovarian follicle, serum estradiol value per follicle was higher for 1st group at $583.0{pm}261.2pg/ml$. 3. When measuring the urine LH surge according to Hi-Gonavi and according to the standard set by three different types of surge, simultameous satisfaction for 1st group, 2nd group, 3rd group was two cases, five cases, four cases respectively at 40%, and the remained cases were composed of numorous type combination which satisfied the two definition, simultaneously in this study, the LH surge starting time was determined only in the cases tow combination were satisfied simultaneously at first, but there are something to study more. In one case of the 3rd group. 4. The concentration of LH surge start in urine and serum of 2nd group was highest at306. $0{pm}287.2IU/l$ and $34.0{pm}9.9mIU/ml$ and 1st group was low at $116.6{pm}66.1IU/l$ and 7.4mIU/ml. The urine and serum value of LH was highest at $1644.4{pm}988.8IU/l$, $65.9{pm}15.0mIU/ml$ for 2nd group, 1st group was low at urine, and 3rd group was low of serum. With pregnancy established, the LH concentration of urine was relatively high but on the contrary the LH concentration of serum was low compared to urine concentration. 5. Time from LH surge start to the maximun of urine and serum value was highest at 15. $7{pm}9.1$ hrs and $10.8{pm}4.9$ hrs for 1st group and 3rd group. With pregnancy established, time was shortened for urine but on the contrary serum showed an increase in time. 6. The concentration of LH which increases with time on urine was highest at 2nd group ($194.6{pm}76.8;IU/hour$). The lowest increase for serum was at 3rd group (2.1mIU/hour). With pregnancy established, urine showed more increase than control group ($266.5{pm}47.4;IU/hour$) and for serum there was similar increase ($3.4{pm}0.8;mIU/hour$). 7. There were two examples of non-typical surge from 1st group and 3rd group each. Among these three cases showed a reestablishment of LH surge after 10-24 hours. 8. Endogenous spontaneous Lh surge occurs once for each 2nd group and 3rd group.