Fresh buffalo milk was standardized to 1.2 g fat 100 g −1 milk. Low-fat, yogurts were fortified with whey protein concentrates (WPCs) 1 g 100 g −1 , Ca- caseinates (Ca-Cns) 1 g 100 g −1 , and spirulina ( Spirulina platensis ) 1 g 100 g −1 powders and their potential effect on the different quality character - istics were studied. Total solids, ash, and fat contents were high in low-fat yogurt added with spirulina powder, while protein content was high in low- fat yogurt enriched with WPCs. The highest level of antioxidant activity ( P < 0.05) corresponded to low-fat yogurt containing spirulina powder, which had high total phenolic compound content. In WPCs-fortified low-fat yogurts, the gel exhibited a various structure with a fine network; and it contained very small pores in size. The highest scores of sensory properties ( P < 0.05) were observed in low-fat yogurt enriched with WPCs.