The rete testis is formed in the fifth week of intra-uterine life. The epithelium along the medial side of the mesonephric ridge thickens to form a genital ridge; cellular gonadal cords at the periphery of the ridge unite with a tubular network from the mesonephric mesenchyme forming the testicular rete. On ultrasound, a range of normal appearances of the rete testis is recognised from ill-defined areas of decreased reflectivity to a coarse tubular appearance (often with finger like projections). In the present review the embryological development of the rete testis is briefly outlined. In addition, the important anatomical variations, pertinent to ultrasound imaging, will be presented.