Nuclear medicine has an important role in the care of newborns and children less than 1 y old. Patients in this age group present with a spectrum of diseases different from those of older children or adults. These patients can benefit from the full range of nuclear medicine studies. In these young children, nuclear medicine studies are more likely to be used to evaluate a wide range of congenital conditions but also can be helpful for evaluating acquired conditions such as infection, cancer, and trauma. This review first will cover the general aspects of nuclear medicine practice with these patients, including the special considerations that can help achieve successful diagnostic imaging. These topics will include clinical indications, imaging technology, instrumentation, software, positioning and immobilization, sedation, local and general anesthesia, radiopharmaceutical doses, radiation risk, and dose reduction. The review then will discuss the specific nuclear medicine studies that typically are obtained in patients in this age group. With extra care and attention to the special needs of this population, nuclear medicine departments can successfully study patients less than 1 y old.