Additive manufacturing (AM) presents unique challenges to the nondestructive testing community, not least in that it requires inspection of parts with complex forms that are not possible using subtrac-tive manufacturing. The drive to use AM for parts where design approaches include damage tolerance and retirement-for-cause with high quality and where safety criticality imposes new QA/QC requirements is growing. This article reviews the challenges faced to enable reliable inspection and characterization in metal powder-based AM processes, including issues due to geometric and microstructural features of interest, the limitation on existing and emerging NDT tech-niques, and remaining technology gaps. The article looks at inspection from powder to finished part, but focuses primarily on monitoring and characterization during the build. In-process, quantitative characterization and monitoring is anticipated to be transformational in advancing adoption of metal AM parts, including offering the potential for in-process repair or early part rejection during part fabrication.