The oil and gas pipeline integrity management system (PIMS) needs right and correct data from transmission lines to achieve its goal which is a secure operation and management with a high reliability and low cost. Meanwhile, intelligent piggings in oil and gas pipelines is one the important and fundamental pipelines’ anomalies (corrosion, metal loss, etc.) monitoring tools and its resulted data is one the important databases in the pipeline integrity management system. Using this database, the ability of to recognize anomalies on time and prevention of failures and explosions in pipelines will be obtained and PIMS goals will be gained. In this paper, the errors in the magnetic intelligent pigging database are investigated which is included “The technological capability of MFL and TFI intelligent pigs, operational condition of piggings (The speed of intelligent pig and pre-cleaning the pipeline), the calculation method of anomalies depth, the issue of anomalies interaction in anomalies clustering, and the calculation of ERF according to ASME B31”. Eventually, the analysis of above-mentioned items in the 40-inch gas pipeline (IGAT1) in the north of Iran has presented with intelligent piggings data implemented in 2001 by ROSEN company and in 2010 by SPETZNEFTGAZ company as a case study. The results presented in this case study shows the importance of faults analysis in the pipeline integrity management (PIMS).