E.ON Ruhrgas operates a gas transmission network with a length of more than 11,300 km. Following a review of existing pigging results in 2003, the criteria for intelligent pipeline pigging were revised based on experience from previous pig runs. It was found that inline inspection is an efficient tool for monitoring the integrity of high-pressure gas pipelines, thus helping to ensure safe and reliable operations. Based on the results found, E.ON Ruhrgas decided to use inline inspection to examine all piggable pipelines greater approx. 20 km in the E.ON Ruhrgas pipeline grid over a period of approx. five to seven years. The good technical condition of the pipelines allows E.ON Ruhrgas to organise the pig runs mainly based on economic and strategic criteria. The results of current inspections are an important input to the company's pipeline integrity management system (PIMS) for piggable pipelines. The necessary pipeline measures can be planned and implemented in an economic manner thanks to the very good quality of the magnetic flux leakage (MFL) results. Also, it is possible to prepare an electronic pipeline log based on the data obtained from the pig runs. Excavation costs can be brought down if the geographic locations of pipeline components and detected features are known and the geographic data can serve as a basis for the GIS system and pipeline surveillance by air.