A study was conducted to investigate the fattening performance, physico-chemical properties of breast meat, vaccine titers in cross bred meat type hybrid chicks fed organic sulfur. Total three hundred and sixty chicks of eight weeks old were replaced in individual cage from 8 to 10 weeks old. Four levels of organic sulfur (0, 1.0, 2.0, 4.0%) containing 45% sulfur were added into basal diet containing CP 19% and ME 2,950 kcal/kg. Weight gain, feed intake, fred conversion were weekly measured. The proximate composition, physico-chemical properties of breast meat, vaccine titer and sensory characteristics were examined at the end of experiment. Weight gain, feed intake and feed conversion of birds fed organic sulfur were not statistically different with control. There were no significant difference in feed intake and feed conversion. However, abdominal fat(%) of birds fed organic sulfur tended to increase compared with control. Crude fat of breast meat decreased significantly in organic sulfur treatments(P<0.05). The red color of breast meat seemed to increase but was not statistically different among the treatments. Cooking loss showed decrements significantly in organic sulfur treatments(P<0.05). Mechanical Hardness, cohesiveness and springiness were prone to be high and gumminess greatly high in breast meat of birds fed organic sulfur addition compared with control. Juiciness tended to increase and greasiness decreased(P<0.05) in organic sulfur treatments by the sensory evaluation. The overall acceptability of the breast meat was the highest at 2.0% organic sulfur added chicks(P<0.01). There were no different blood cholesterol, AST, ALT and BUN.