Training and instruction of personnel are important components of animal care and use programs because they help to ensure the health and welfare of the animals and the integrity of the research or testing results. Training also helps to promote the consideration of alternatives, recognition of animal pain and distress, appropriate use of pain-relieving agents, aseptic technique, pre- and post-procedural care, and personnel health and safety. While individuals who provide the care for or conduct research or testing in laboratory animals should take personal responsibility for ensuring that they have the skills to perform their duties, the institution is ultimately responsible for ensuring their competency. The institution is also responsible for providing the training or instruction that is required by federal legislation, regulations, and policies. The institutional animal care and use committee (IACUC) is responsible for ensuring, as part of their review of research activities, that the personnel are capable of performing the procedures described. The IACUC must also assess the institution's training program as part of their semiannual animal care and use program review and make recommendations regarding training to the institutional official. This article provides a comprehensive overview of the US regulatory mandates for training and personnel qualification.