Chromosomal microarray analysis (CMA) is a first step test used for the diagnosis of patients with developmental delay, intellectual disability, autistic spectrum disorder, and multiple congenital anomalies. Its widespread usage has allowed genome-wide identification of copy number variations (CNVs). In our study, we performed a retrospective study on clinical and microarray data of 237 patients with developmental disabilities and/or multiple congenital anomalies and investigated the clinical utility of CMA. Phenotype-associated CNVs were detected in 15.18% of patients. Besides, we detected submicroscopic losses on 14q24.3q31.1 in a patient with speech delay and on 18q21.31q21.32 in twin patients with seizures. Deletions of NRXN3 and NEDD4L were responsible for the phenotypes, respectively. This study showed that CMA is a powerful diagnostic tool in this patient group and expands the genotype-phenotype correlations on developmental disabilities.