We reviewed cytogenetic studies that have been done in 1,000 consecutive non-oncology samples that were referred to the Cytogenetics Unit at King Khalid University Hospital, Riyadh, Saudi Arabia. The cases were grouped according to the referral diagnosis and the requested cytogenetic service. The frequency of the different types of numerical and structural abnormalities was determined and the relative frequency of cases with abnormal karyotype was calculated in each group. This study should assist physicians in Saudi Arabia and surrounding countries by increasing the awareness of the frequency of cytogenetic abnormality in different diagnostic groups. It also gives figures for comparison with other countries and research centers.