Background: The aim of this study is to identify the profile of patients being referred for cytogenetic analysis in the medical genetics and oncogenetics unit of FEZ Hassan II University Hospital, to determine the prevalence and type of chromosomal abnormalities in the different groups and to compare the results with those of similar studies done in other countries. Materials and Methods: We examined the analysis of 1,200 cases referred to the medical genetics and oncogenetics unit of FEZ, between September 2009 and June 2014. They were grouped according to the indications of the cytogenetic study. Frequencies of the different numerical and structural abnormalities were calculated. The relative frequency of cases with abnormal karyotypes was also determined in each group. Results and Discussion: 70,4% cases were referred from pediatric department and 54,4% are aged under 5 years old. Cytogenetic testing was essentially requested for Dysmorphism (25,6%), Mental Retardation (16%), Down syndrome (14%), girls’ growth retardation (13,8%) and for recurrent miscarriage (12,6%). Of the 1200 cases studied, 79% had a normal karyotype and 21% had chromosomal abnormalities. The most common chromosomal abnormality was trisomy 21 (11,7%) followed by Turner syndrome (2,1%) and Klinefelter syndrome (1,5%). Conclusion: This study compares the results of cytogenetic analysis of chromosomal abnormalities in the north Moroccan population with other studies and research centers. This comparison will help Moroccan clinicians to determine the priority for requesting a cytogenetic analysis in individual cases.