Objective: We present 20-days old boy with congenital heart DEFECTS, partial syndactyly and mild facial anomalies including thin upper lip and high arched eyebrows. CHROMOSOMAL analysis revealed an extra CHROMOSOMAL material on the long arm of one chromosome 5, resulting in 46, XY, dup (5) (q22q31. 3). We compare the clinical characteristic of our patient with those of the previously reported cases with 5q duplication in an attempt to define the phenotype-genotype correlation. Introduction: Partial duplication of long arm of chromosome 5, based on the length and the loci can lead to different clinical problems and phenotypic features. These include congenital heart DEFECTS, growth and developmental delay, facial anomalies, psychomotor retardation, syndactyly and brachydactyly. To our knowledge, twelve patients have so far been reported with the duplication of long arm of one chromosome 5. Patient information: The patient is a 20-days-old boy and the only child. He was born at 37+ 0 weeks of gestation after an uneventful pregnancy. His weight at birth was 2570 grams and height was 45 centimetres. His mother was 26 years old and had no history of abortion. She does not have any familial relationship with her husband. Both his parents have normal karyotype. Conclusion: Cytogenetic investigation in patients with congenital heart DEFECTS is of great value and is highly recommended.