This chapter discusses sperm analysis by macroscopic inspection and microscopic examination. Spermatozoa are not the only cellular constituents of human semen. Every human semen sample is contaminated with leukocytes. The conventional semen profile consists of an analysis of sperm count, motility and morphology in the unfractionated ejaculate. The introduction of computer-aided sperm analysis (CASA) systems has allowed detailed quantitative analysis of sperm motility to be undertaken that are characterized by high precision. Cervical mucus is undoubtedly one of the most severe barriers that spermatozoa have to traverse on their route to the site of fertilization in vivo. The ability of acrosome-reacted human spermatozoa to fuse with the vitelline membrane of the oocyte can be assessed by the hamster oocyte penetraton assay. Male infertility differs from female infertility because it is fundamentally not an endocrine condition. Most infertile men are normogonadotrophic and possess normal androgen levels.