This chapter focuses on imperfect inventory control model with breakdown and repair process. Sixteen mathematical models under different assumptions such as stochastic defective, stochastic demand rate, stochastic repair time, stochastic lead time, and stochastic failure rate are presented. Random shift in production, rework process, shortage, failure during rework, deterioration process, etc., are other assumptions considered in descriptions of presented problems. For all presented models, solution models and numerical examples are provided to show the applicability of models.