In a 6-week-old male infant who was referred because of an umbilical hernia and a non-purulent omphalitis, type-I leukocyte-adhesion deficiency was diagnosed. Additional clues were persisting leukocytosis upon clinical improvement under antibiotic treatment and a late falling off of the umbilical remnant in the patient's history. After cure by antibiotic therapy, life-long antibiotic prophylaxis was prescribed. Leukocyte-adhesion deficiency syndromes are rare, autosomal recessive, hereditary immunological disorders. The basis of these disorders is found in the absence or defective function of adhesion molecules that are needed for an interaction between the leukocytes, especially neutrophilic granulocytes, and endothelial surfaces. On the basis of clinical signs and symptoms and laboratory findings, two types of leukocyte-adhesion deficiency can be distinguished. Type I is marked by a disorder in the migration of granulocytes through the endothelium, in which integrins are involved. In type II, there is a disorder in the first step in the adhesion of granulocytes to the endothelium, in which selectins are involved. These conditions already become manifest in childhood. Therapy is generally symptomatic and consists mainly of the prevention and treatment of infection. Cure is sometimes possible by means of allogenic bone-marrow transplantation.