Malassezia furfur is important in the pathogenesis of a number of dermatologic diseases including seborrheic dermatitis in adults. It has also recently been suggested that M. furfur might be the etiologic agent in infantile seborrheic dermatitis (ISD). We studied the presence of M. furfur in 21 children with the clinical diagnosis of infantile seborrheic dermatitis. Laboratory analyses showed aberrant patterns of essential fatty acids (EFA) in serum characterized by elevated levels of 18:1w9 and 20:2w6. Samples for M. furfur were taken from the foreheads and chests of children with infantile seborrheic dermatitis at the time of diagnosis, directly after treatment to complete healing, and after 1 year with no signs of infantile seborrheic dermatitis. All the patients were treated topically with borage oil containing 25% gammalinolenic acid (GLA). No reduced growth of M. furfur was seen on contact plates prepared with borage oil. The growth of M. furfur seems not to be related to the clinical symptoms in ISD.