Azoospermia is diagnosed in approximately 1 percent of the general population and in up to 15 percent of infertile men. Of these men, 15–20 percent can be further categorized as having obstructive azoospermia [1]. Men with obstructive azoospermia have preserved spermatogenesis, allowing for either surgical repair of their obstruction or sperm retrieval to be used in conjunction with in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI). The obstruction can occur anywhere along the passage of sperm from the efferent ducts within the testis, along the epididymis, through the vas deferens, the ejaculatory ducts, or the distal penile urethra. Causes of obstructive azoospermia can be congenital, acquired, or idiopathic (Table 5.1) [2]. Vasectomy and iatrogenic obstruction to the vas deferens at the time of inguinal hernia repair are the most common causes of acquired obstructive azoospermia. Congenital bilateral absence of the vas deferens (CBAVD) is the most common congenital cause [3,4]. In men with obstruction of the epididymis or vas deferens, microsurgical reanastomosis at the site of obstruction can be done with good fertility-related outcomes. Those who do not wish to undergo surgical repair of their obstruction, have failed surgical repair, have CBAVD, or have an unclear/multifactorial cause of their obstruction can be treated with sperm retrieval and ICSI [5]. Percutaneous epididymal sperm aspiration (PESA), microsurgical epididymal sperm aspiration (MESA), and the recently described minimally invasive epididymal sperm aspiration (MIESA), are all techniques that allow successful retrieval of sperm from the epididymis in men with obstructive azoospermia (Table 5.2).