Inspection and fitness-for-service (FFS) of critical in-plant piping systems remains an ongoing concern for the chemical industry. Recent failures in the US indicate that there is a present and severe risk in piping systems. Historically, unpiggable in-plant piping can now be inspected with advanced smart pigging technology for complete ultrasonic inspection. High-resolution inspection data is analyzed to identify the locations and degree of corrosion and piping deformations. This article discusses current industry experience with the inspection and assessment of in-plant piping systems using advanced smart pigging technology. Utilizing more advanced inline inspection and assessment technology helps operators reduce inspection costs associated with difficult-to-inspect pipelines and piping systems; reduce maintenance costs by more accurately pinpointing anomalies and assessing FFS conditions; and accurately determine the actual conditions for lines previously deemed unpiggable. (C) 2011 American Institute of Chemical Engineers Process Saf Prog 30: 334-337, 2011