Rationale: In dermatology anesthetics are frequently injected or topically applied to achieve local anesthesia. Injectable anesthetics are effective but uncomfortable during administration, especially for people who are needle phobic. Application of topical anesthesia is painless but time consuming and often only partial aesthesia is achieved due to the barrier function of the stratum corneum. (Manuskiatti, Triwongwaranat et al. 2010) Penetration of local anesthetics could be enhanced by pretreatment of the skin with ablative fractional lasers (AFXL) which locally disrupts the stratum corneum by creating an array of microscopic ablation channels. (Sklar, Burnett et al. 2014) In a previous pilot study, conducted at our institute, we demonstrated that effective anesthesia could be achieved within ten minutes after application of a topical anesthetic on skin pretreated with AFXL at painless settings. (Meesters, Bakker et al. 2015) However, little is still known about the role of the type of fractional laser used (e.g. CO2 or Er:YAG laser), the laser settings, the type of anesthetic and the occlusion time on the efficacy of the anesthesia.