Porokeratosis of Mibelli is a rare genodermatosis characterized by a disorder of keratinization. None of the currently available therapies is effective in all cases and this situation exposes the patient to multiple treatment cycles. We describe the successful use of topical imiquimod 5% cream in the management of porokeratosis of Mibelli of the axillae in a 12-year-old girl. Treatment with imiquimod was effective, probably due to the area of application, where large hydrated skin folds are found, which helps penetration of the drug on the stratum corneum.