Down Syndrome (DS) is the most common chromosomal aberration in humans with an occurrence of 1/800 live births. There are nearly 80,000 trisomic 21 currently in Algeria. The aim of our study is to give a scociodemographic and anthropoligical profile of children with DS from Tlemcen. A retrospective study of 135 diagnosed DS children, who had a specific clinical features. These children are admitted in six psychoeducational centers for mentally unsound children - PMC – and the UMD association located in different regions of Tlemcen from 2011to 2017. We collected data using a pre-established questionnaire for parents and referring to children's medical and administrative records. The mean DS age was 11.73 years, with a sex-ratio of 2.06. Parental consanguinity has been reported in 14.07% of cases. The mean maternal age at birth was 36.29 years. Advanced maternal age is one of several risk factors for giving birth to a child with SD. This syndrome remains the most chromosomal aberration in Tlemcen's population as for other world populations. However, to better understand the prediction of DS we should increase the number of sample analyzed with the study of other factors.