Background: Seminal fluid of males is varied in quality, not only between males but also within a single sample. A verity of in vitro sperm preparation techniques were developed to separate normal and motile spermatozoa from other constituents of sample to provide successful assisted reproductive techniques. Objectives:The goal of this study was to compare the effects of the four in vitro sperm activation techniques on sperm function parameters specially sperm motility ofasthenozoospermicand oligozoospermicsemen samples. Subjects, Materials and Methods:Thirty-five asthenozoospermic and fifteen oligozoospermic men were participated in this study during their attendance to the Infertility Clinic at High Institute for Infertility Diagnosis and Assisted Reproductive Technologies; Al-Nahrain University. Collection of semen samples and seminal fluid analysis was done according to WHO (1999) and WHO (2010). Each semen sample was divided into four parts. The first one prepared as in vitro sperm activation using the direct swim-up technique, the second using indirect swim-up technique,the third using density gradient centrifugation technique, while the last part prepared using density gradient centrifugation and Caffeine(combined techniques). Results: A significant increase was observed in the sperm function parameters including sperm motility and morphologically normal sperm for asthenozoospermic and oligozoospermic samples when using density gradient centrifugation and Caffeine as compared to density gradient centrifugation alone.Also, there was a significant increase was observed in the same sperm function parameters when using density gradient centrifugation as compared to direct swim-up technique and indirect swim-up technique. Conclusion: In this study, the outcome of sperm function parameters using combined density gradient technique with Caffeine were higher than other techniques, especially when using a low quality of semen samples such as decreased sperm motility, therefore it was fit in cases ofasthenozoospermia and oligozoospermia which are taken as examples of infertile group in this study.