Even if yogurt is one of the oldest fermented dairy products, it remains very popular today because of its image as ‘modern’ fermented food, resulting from its attractive nutritional properties and its increasing diversification, associated with the industrialization of its manufacture. After a short definition of yogurt and fermented milks, the microbiological characteristics and the main biochemical mechanisms involved in their manufacture are presented. The three main steps of the manufacturing process, that is, the mix preparation, fermentation, and harvesting/packaging, are then developed. Finally, the main microbiological, physicochemical, and sensory analyses and controls of the yogurts' quality are summarized.