Tacrolimus ointment is used worldwide to treat atopic dermatitis. Although tacrolimus ointment is not suitable for clinical admixtures, it is often mixed with various ointments or creams, such as corticosteroids, antibacterial agents, and moisturizing agents. There is only one report of quality testing of admixtures of tacrolimus ointment with adaparene gel (Differin^® Gel). In this study, we used HPLC to evaluate the pharmaceutical stability of tacrolimus mixed with eight different dermatologic ointments or creams. No decrease in the tacrolimus content was observed in any of the mixtures after 4 weeks of storage at room temperature, indicating that tacrolimus admixtures are stable.