Abstract: Objective To explore the diagnosis strategy of Rubinstein-Taybi syndrome. Methods SNP-array technology was used to analyze the variation of whole genome copy number in one patient whose clinical features were in accord with the diagnosis of Rubinstein-Taybi syndrome. Results Two-months-old male patient had been detected to have 1.8 Mb deletion mutation in 16p13.3 region (chr16: 2903942-4748851), in which the pathogenic CREBBP gene was located. Conclusions Chromosomal microarray analysis (CMA) technology, such as SNP-array, can be used to make a molecular diagnosis of Rubinstein-Taybi syndrome.