This chapter aims at presenting the main issues concerning the freezing of probiotic bacteria, in order to allow these bacteria to survive and maintain their biological properties. Part 1 Introduction Part 2 Principles of Freezing and Biological Consequences on Probiotic Bacteria Part 3 Biological Responses of Probiotic Bacteria to Freezing Stress Part 4 Improvement of Freezing Resistance of Probiotic Bacteria by Controlling Freezing and Storage Conditions Part 5 Improvement of Freezing Resistance of Probiotic Bacteria by Controlling Fermentation and Post-fermentation Conditions Part 6 Freezing Technology and Control of Quality during Probiotic Starter Production Part 7 Conclusion