Patients suffering from chronic lymphocytic leukemia often develop actinic keratosis (AK) and squamous cell carcinoma in sun-exposed areas. In these particular patients, who have a suboptimal immune function, AK treatment can be particularly challenging. We report the case of a patient who failed to respond to most AK treatments, including 5-FU, imiquimod and photodynamic therapy, but responded to ingenol mebutate. We started with 3 applications of 150 μg/g (registered treatment of the scalp) and also 2 applications of 500 μg/g (registered in for trunk and extremities). Both treatments were well tolerated, but only the latter led to significant clinical success. This suggests that 500 μg/g of ingenol mebutate may represent an interesting therapeutic option in patients with mild immunosuppression.