Membrane distillation crystallization (MDC) is an innovative concept of combining the strengths of membrane distillation into crystallization processes because crystallization is one of the major unit operations in chemical industries. The hybrid technology is of growing interest due to some important advantages, such as the controlled rates of supersaturation, nucleation, and crystal growth, fast crystallization rates, enhanced heterogeneous nucleation on membrane surface, etc. This chapter focuses on the combination of MD and crystallization technologies for simultaneous production of fresh water and inorganic salt crystals. We intend to provide a state-of-art review on (1) different crystallizers in MDC, including traditional crystallizer and solid hollow fiber cooling crystallizer (SHFCC) and (2) novel integrated MDC systems, such as simultaneous membrane distillation – crystallization and MD-SHFCC. In addition, future research efforts to make MDC a more liable operation are also discussed.