This paper presents a case of the moderate form of Leukocyte adhesion deficiency type 1 (LAD-1) in a 4 year-old boy. LAD-1 is a rare, inherited immunodeficiency that affects 1 in 1 million people yearly. Affected patients are susceptible to recurrent bacterial and fungal infections, impaired pus formation and delayed wound healing. In the oral clinical finding, more important is a generalized prepuberal periodontitis that can affect the primary and permanent dentitions. For this reason cooperation between dentists and pediatricians is essential in these patients. Evaluating immune system in these patients included peripheral blood leukocyte counts, measurement of serum immunoglobulin levels, assessment of complement level and function, flow cytometric analysis of lymphocyte subsets, and tests of phagocytic function (nitrobluetetrazolium test (NBT)). In families with known molecular defect, an earlier prenatal diagnosis is possible by chorionic villi biopsy. The most important focus should be to control infections. Treatment includes systemic antibiotics and in many cases bone marrow transplantation.