This study aims to describe the implementation of mastery learning (complete learning) in Islamic Religious Education learning (both planning, implementation, evaluation, learning outcomes and follow-up) in SMA Negeri 2 Bogor; also to provide a clear explanation of the implications of mastery learning on students' achievement of Competency Standards (SK) in Islamic Education learning. This research is a qualitative field research. The approach used is descriptive qualitative and data collection uses the method of observation, interviews, documentation and triangulation. The data analysis used was descriptive analytical and interpretive. The results show that SMA Negeri 2 Bogor has implemented the mastery learning strategy as an effort to achieve SK in learning (PAI), especially - more intensively - since the implementation of the CBC in 2004 and KTSP in 2006, but the implementation has not been maximal. and needs further improvement. Implementatively, the mastery learning strategy pays close attention to individual differences, marked by the existence of follow-up programs in the form of remedial, enrichment and acceleration programs, which of course become necessary being. so that students achieve competency completely. The implication is that the achievement of SK depends on the achievement of Basic Competence (KD), and the achievement of KD is very dependent on the achievement of indicators, and vice versa. The completeness is based on the Minimum Completeness Criteria (KKM) that have been determined in Islamic Education learning, so that students have competence and performance that can be measured (measurable) and can be observed (observable) as an indicator of successful learning completely.