OBJECTIVE: The use of combined oral contraceptives (COC) as a contraceptive method is still limited in Japan, used only by 1.1% of women of reproductive age. The usage pattern of COC, such as continuation and preparation switch, between COC generations was investigated using large datasets. METHODS: This descriptive study spanning from 2006 to 2014 used nationwide prescriptions based on administrative databases, including both reimbursed and non-reimbursed drugs. All the first-time COC users were included as a cohort. Usage patterns considering trends, continuation, and switch of COC generations were also investigated. RESULTS: Of the 38,123 patients, the overall mean age at initial use of COC was 32.9 years. Of the first-time users, 51.2%, 23.7%, 5.6%, and 19.5% received first-, second-, third-, and fourth-generation COCs, respectively. The overall rate of continuation was 59.1%, and the rate of first-time use with switching to other generations within 180 days was 3.1%. CONCLUSION: We revealed the actual usage of COC in Japan with frequent prescriptions of first- or fourth-generation COCs and relatively high age at initial use. Moreover, the COC continuation rate was low, and switch was limited. Further studies into its proper usage are recommended.