This study aimed to reveal the characteristics of prescribing hypnotics at Japanese medical institutions, with data on medical payments from 4 large-scale Japanese health insurance organizations with almost 320 000 members. The study targeted the data from 4807 patients, aged 20 to 74 years, who were prescribed hypnotics during a 3-month surveillance period. The prescription rate for hypnotics was estimated at 3.66% based on the national population census in 2005. The rate significantly increased with age, especially among women over 60, and markedly increased along with the number of comorbid physical diseases. The percentage of prescriptions from the specialties of psychiatric, neurologic, and psychosomatic medicine held at 37.6%. However, the prescribed doses were still significantly higher for these specialties than for general medicine. Short-acting and ultra short-acting hypnotic medications were frequently prescribed, especially in the group of individuals of advanced age. Due attention should be paid to the risk–benefit balance in prescribing hypnotics to elderly individuals as those having high prescription rates. Although the present study is based on specific groups, the findings provide an important insight into the characteristics of Japanese prescribing hypnotics.