Objective: To describe the application of preimplantion genetic diagnosis to a carrier couple for leukocyte adhesion deficiency type I disease (LAD- 1), to achieve a healthy pregnancy. Design: Case report. Setting: Reproductive center and university hospital. Patient(s): A couple in which both partners were carriers for LAD- 1; the female partner carried a G400A substitution in exon 4, and the male partner carried a C562T substitution in exon 5 in theCD18 gene. Intervention(s): Day- 3 cleavage- stage biopsy after standard in vitro fertilization (IVF) and genetic analysis of blastomeres for two mutations, along with a marker from chromosome 21. Main Outcome Measure(s): Birth of a child unaffected with LAD- 1. Result(s): Fifteen oocytes were retrieved, of which 10 were fertilized; eight embryos were suitable for embryo biopsy. After genetic analysis, three embryos were found to be unaffected. According to embryo morphology, two embryos were transferred, resulting in the birth of an unaffected child. Conclusion(s): This is the first report of preimplantion genetic diagnosis for LAD- 1. The successful birth of a healthy child provides evidence that for carrier couples of diseases for which traditional prenatal diagnosis and the decision of whether to terminate a pregnancy might not be acceptable, the application of PGD provides an alternative. Objective: To describe the application of preimplantion genetic diagnosis to a carrier couple for leukocyte adhesion deficiency type I disease (LAD-1), to achieve a healthy pregnancy. Design: Case report. Setting: Reproductive center and university hospital. Patient (s) : Female partner carried a G400A substitution in exon 4, and the male partner carried a C562T substitution in exon 5 in the CD18 gene. Intervention (s): Day- 3 cleavage- stage biopsy after standard in vitro fertilization (IVF) and genetic analysis of blastomeres for two mutations, along with a marker from chromosome 21. Main Outcome Measure (s): Birth of a child unaffected with LAD- 1. Result (s): Fifteen After embryo morphology, two embryos were transferred, resulting in the birth of an unaffiliated Conclusion (s): This is the first report of preimplantion genetic diagnosis for LAD- 1. The successful birth of a healthy child may evidence that for carrier couples of diseases for which traditional prenatal diagnosis and the decision of whether to terminate a pregnancy might not be acceptable, the application of PGD provides an alternative.