Isochromosome 18p is a rare chromosomal disorder that occurs with a frequency of approximately one in every 180,000 live births, and affects both genders equally. MOst cases result from a de novo formation. In the literature, there are currently only a small number of reports that describe the phenotypic and clinical features of Isochromosome 18p. In this article, we report six cases that displayed the phenotypic and clinical features of Isochromosome 18p, and which were subsequently confirmed by conventional karyotyping and fluorescence in situ hybridization. We also discuss the clinical features of these patients in the context of the cases previously reported in the literature.