Topical photodynamic therapy (PDT) is an effective method when treating extensive areas of sun-damaged skin with multiple actinic keratoses (AKs) (field cancerization) on areas such as the forehead and scalp, and offers excellent cosmetic outcome. The major side-effect of PDT is the pain experienced during treatment. To investigate whether nerve blocks could provide adequate pain relief during PDT of AKs on the forehead and scalp. Ten men with symmetrically distributed and extensive AKs on the forehead and scalp were included in the study. Prior to PDT one side of the forehead and scalp was anaesthetized by nerve blocks while the other side served as control. The mean visual analogue scale (VAS) score on the anaesthetized side was 1 compared with 6.4 on the nonanaesthetized side during PDT. This difference was significant (P<0.0001), implying that nerve blocks reduce VAS scores during PDT. The results of the study support the use of nerve blocks as pain relief during PDT of field cancerization on the forehead and scalp, although individual considerations must be taken into account to find the most adequate pain-relieving method for each patient.