The semen preparation medium that yields good semen quality is one among various important factors in the process of infertility treatment. The objective of this study was to compare the semen analysis parameters before and after preparation with 3 semen preparation media i.e. PureSperm® (Nidacon, Gothenburg, Sweden), Sil-Select PlusTM (Fertipro, Beernem, Belgium) and SpermGradTM (Vitrolife, Gothenburg, Sweden) for enhancement of good semen quality. The total of 28 males of infertile couples attending Fertility Clinic of Thammasat University Hospital during the year 2007 were studied. Their semen (pre-washed) were analyzed for semen analysis parameters according to WHO1 and Kruger’ strict criteria2 and then equally divided into 3 aliquots and processed with 3 semen preparation media followed by semen analysis once again (post-washed). The sperm concentration, motility, progressive motile concentration (PMC), morphology, DNA damage and protamine deficiency of before and after preparation were compared by paired t-test with significance at P < 0.05 The mean percentage of sperm motility, PMC, rapid motility and normal morphology were significantly increased where the mean percentage of slow motility, sperm head defect, sperm concentration and protamine deficiency were significantly decreased after preparation with all 3 media. The DNA damaged sperm was significantly decreased in the post-washed with PureSperm® and Sil-Select PlusTM but significantly increased with SpermGradTM. From the results obtained in this study, it could be concluded that PureSperm® may be suitable for both IUI and IVF techniques, since it yielded the best motile sperm and it may be also good for ICSI because it gave low percentage of DNA damaged sperm. Sil-Select PlusTM is probably best for ICSI since it gave lowest percentage of DNA damage sperm, whereas SpermGradTM had highest percentage of DNA damage, thus, it is surely not suitable for ICSI procedure. Anyhow, SpermGradTM may be moderately good for IUI since it had high percentage of motility and of normal morphology with lowest percentage of head defect but percentage of abnormal embryo may be increased.