The effectiveness of hot thermal retention system which was being used in 3 general hospitals, A,B, and C in Seoul was evaluated in terms of time-temperature relationship. The results of the study were summrized as follows: 1) The serving temperature of steamed rice using insulated bowls were significantly higher than those of using no thermal support. 2) The serving temperatures of soup using insulated bowls were significantly higher than those of using no thermal support. 3) The serving temperatures of meat of fish dishes using insulated bowls as well as warmer cabinet were significantly higher than other groups such as using warmer cabinet only, using insulated bowls only, and using no thermal support. 4) However surveyed serving temperatures of meals using hot thermal retention system were not whthin the range of temperature criteria.