This chapter discusses various aspects of genetic disorders in children in detail. Genetic disorders include single gene disorders, chromosomal disorders, polygenic or multifactorial inheritance defects, cytoplasmic inheritance or mitochondrial inheritance, fresh mutations leading to disease, cancer or malformations, and acquired diseases having varying degrees of genetic influence. Autosomal dominant traits, autosomal recessive traits, consanguinity, and X-linked inheritance, can be a cause of these disorders. Various stable chromosomal alterations occur in humans, leading to various clinical conditions such as terminal deletions, interstitial deletions, isochromosomes, and translocations. In Down’s syndrome, chromosomal abnormalities noted children include pure trisomy, chromosome mosaicism, and robertsonian translocation. The peculiarity in mitochondrial inheritance is that it is always the mother who transmits the traits to the offspring, both male and female. In Patient with suspected genetic disorder, going through previous health records of the patient and the family members and relevant basic investigations, hematologic, biochemical radiologic is necessary.