Ultrasound forms an important part of the assessment of the testicle. Nevertheless, there are a number of situations in which clinical and radiological assessment is unable to provide a definitive diagnosis of a testicular lump. In these situations, historically, either open biopsy or orchidectomy has been performed. Ultrasound-guided percutaneous testicular biopsy is an alternative, less invasive method of obtaining histological diagnosis. Here we describe the rationale, technique and potential uses of the technique.