This review describes the current, emerging and potential applications of ultrasonography in the field of firstopinion sheep veterinary practice. The most widespread application is pregnancy diagnosis, where both transrectal and transabdominal ultrasonography offer a highly sensitive tool for, among others, detection of pregnancy, identification of foetal number and diagnosis of uterine abnormalities, e.g., metritis. The diagnostic applications of ultrasonography for imaging the lungs, heart, male genitourinary system and superficial swellings are also described. Through review of recent research in sheep and by analogy from applications in other animal species, the potential role of ultrasonography in screening programmes for cystic echinococcosis or ovine pulmonary adenocarcinoma, diagnosis of ocular and laryngeal disease and localisation of Coenurus cysts is explored.