During the last decades, the use of ultrasound as a fast and accurate tool for pregnancy diagnosis in sows hasincreased. Ultrasonography has also shown to be an appropriate method to visualize the ovaries of gilts and sows toeither determine the time of ovulation or to diagnose ovarian dysfunctions. By monitoring the ovaries before thefirst insemination in gilts, or after weaning in sows, it is possible to estimate the time of ovulation and subsequentlyto determine the optimal time of insemination. Therefore ultrasound testing can be a helpful tool in herds sufferingfrom reproductive failure due to insufficient estrous detection and subsequently an incorrect insemination time.Ultrasonography can also be used for diagnosing ovarian abnormalities, such as ovarian cysts and inactive ovaries.In this way, it can be helpful in the decision to cull sows that are not suitable for breeding purposes. Ultrasoundtesting of the ovaries may therefore be advised as a tool to solve and prevent fertility problems in specific pig herds.