The evidence level for the recommended initial TDM timing was low in the guidelines, and few studies have evaluated the Cmin according to the day after the start of voriconazole therapy in a real-world setting.It has been reported that a trough level close to the steady-state concentration was obtained after 2–5 days of voriconazole therapy when loading doses had been administered. Because the trough level on day 2 reflects only the concentration achieved by the loading doses on the first day of the therapy, the initial TDM on days 3–5 has been recommended in the recent guidelines.However, a further increase in the Cmin level was observed in TDM conducted after 5 days in patients with an adequate voriconazole regimen, including loading doses, in this study.