The effect of adding Cassia fistula polysaccharide (CFP) at levels of 1%, 1.5%, or 3% (w/w) on the physicochemical properties of natural yogurt was analyzed. The physical stability (wheying-off and syneresis), texture parameter (hardness, adhesiveness, cohesiveness, springiness, gumminess, chewiness) and flavor compounds formation (acetaldehyde and diacetyl) were investigated. Yogurt enriched with CFP showed significantly lower wheying-off and syneresis compared to the control, with 2% CFP having the lowest values. Hardness decreased as CFP concentration and storage time at 4°C increased. Adhesiveness was also lower in CFP-enriched samples but increased during storage. Adding 2% CFP reduced consistency, cohesiveness, and springiness, indicating a softer texture. Gumminess and chewiness were lower in CFP-enriched samples, with 2% CFP yogurt showing the lowest gumminess (0.31 N). Acetaldehyde levels in CFP-enriched yogurt were lower than the control and decreased over time, while diacetyl levels increased during storage but remained lower than in the control.