With the advent of the techniques of reproduction, the functions of this fluid on the sperm function became a topic of lesser interest to the embryologist, urologist and andrologist. The interaction of spermatozoa with seminal plasma often goes unnoticed, but it is very likely that many substances produced by male accessory glands have impact on the sperm physiology. Seminal fluid contains several components besides spermatozoa; many of them are produced by a specific tissue and can be useful markers of secretion of the glands. The information in the 5th Manual of World Health Organization is very limited with respect to the interpretation in several characteristics abnormally high in semen. Male accessory glands secrete several factors such as alpha-glucosidase, fructose, prostaglandins, bicarbonate and citric acid among others, which are crucial for sperm physiology. This chapter deals with the interpretation of markers of accessory glands and their relation to some pathologies such as varicocele, infections, obstructions of the seminiferous pathways and some hormonal alterations.