The high prevalence of hospital-acquired infection has a significant impact on the operating cost of hospitals in Thailand. A nationwide questionnaire survey was conducted to determine how frequently unnecessary infection control procedures were performed. Nearly 17% of hospitals routinely cleaned floors with disinfectants; 48% installed ultraviolet lights in the operating room; 57% performed routine environmental cultures; 68% reported fogging of the operating theatres and the isolation rooms; wearing a protective gown in the intensive care units was routine in 57% of the surveyed hospitals; 30% of hospital laundries set temperatures unnecessarily high and sterile gloves were overused in 25% of hospitals. Large cost reduction can be achieved by discontinuing these practices.