Chlorine content of bituminous coal was determined and its behavior during carbonization was investigated. The chlorine content in the metallurgical coals used in this experiment was between 100 and 1, 500ppm. Most chlorine in coal and coke was removed by washing with water. CaO addition to coal increased the chlorine residue ratio in coke. The residue ratio of chlorine in coke increased with increasing Ca content in coal. This is considered because chlorine in coal is released as HCl, which is trapped in coke again in the form of CaCl2. The chlorine residue ratio of coke produced in actual coke oven was higher than that of coke produced in laboratory scale tube furnace. This is considered because released gas from coal has more chances to contact with calcium in the actual coke oven than in the tube furnace. Furthermore the removal of chlorine from NaCl was promoted by co-carbonization of NaCl with coal. This implies that H2O derived from coal decomposition may help chlorine to be released.