Prostate cancer (PCa) is the most common cancer in men. Nowadays, it is diagnosed through the test of serum prostate-specific antigen (PSA) and rectal examination; however, there is still debate about the PSA-based diagnosis. Seminal fluid (SF), contains a high concentration of subcellular lipid-bound microparticles, traditionally termed "prostasomes", that are extracellular vesicles (EVs) released into the extracellular space by prostate gland's epithelial cells. These vesicles, first described in 1982 promote motility of sperm cells, regulation of sperm cell capacitation, acrosome reaction and immune suppression within the female reproductive tract. It was demonstrated that prostasomes could contain PCa specific molecular fingerprints that can represent the status of their parental cells. Until now the analysis of isolated prostasomes released by PCa cells has proved several advantages compared to the analysis of parental cells. Moreover, the molecular composition of prostasomes could reflect their capacity to influence PCa growth and metastasis. In this review, we discuss the role of prostasomes in PCa, focusing in the possibility of exosomes to represent a non-invasive test for PCa diagnosis and as a possible agent for enhance the sexual transmission diseases (STD) through immunomodulation.