Kindler syndrome is a genodermatosis that combines clinical features of hereditary epidermolysis bullosa and poikiloderma congenitale. The ultrastructural level of blister formation has not been well characterized. Two brothers with Kindler syndrome had a history of primarily acral blistering since infancy as well as photosensitivity. Blister formation was found through the basal layer. Marked tonofilament clumping was found in intact keratinocytes adjacent to the blisters. The younger brother (aged 21 years) had actinic keratoses, which have not been previously described in Kindler syndrome. The findings of basal layer separation in both spontaneous and induced blisters in Kindler syndrome suggest this is the true level of blister formation. The finding of actinic keratoses in a young patient with Kindler syndrome suggests that some patients may be at increased risk for early solar-induced skin disease. The presence of clumped tonofilaments in keratinocytes adjacent to blistered areas suggests an abnormality of keratin 5 or 14 could be present and may play a role in blister formation in patients with Kindler syndrome.