Fungal dermatitis was diagnosed in two captive gray seals (Halichoerus grypus) and four harbor seals (Phoca vitulina) between 1992 and 1994. Trichophyton mentagrophytes, Malassezia spp., and Yarrowia (Candida) lipolytica were isolated. Erythematous, thickened, alopecic skin lesions were present on the face and on the flippers, particularly around the nail bed. The two most important environmental factors associated with development of fungal dermatitis appeared to be excessive chlorination of pool water and warm water temperature.