The physiology of ejaculation includes emission of sperm with the accessory gland fluid into the urethra, simultaneous closure of the urethral sphincters, and forceful ejaculation of semen through the urethra. Emission and closure of the bladder neck are primarily alpha-adrenergically mediated thoracolumbar sympathetic reflex events with supraspinal modulation. Ejaculation is a sacralspinal reflex mediated by the pudendal nerve. The most common ejaculation disorder is premature ejaculation, but there is little agreement regarding the definition of this disorder or its etiology, diagnosis, and treatment options. Premature ejaculation is in fact classically considered psychogenic in nature. However, recent data have demonstrated that prostatic inflammation/infection has been found with high frequency in premature ejaculation, suggesting a role of prostatic pathologies in the pathogenesis of some cases of failure of ejaculatory control. Rarer disorders are emission and ejaculation failure and urine contamination of semen. The new use of diagnostic procedures and the availability of pharmacological aids place this topic in the mainframe of medical sexology.