Chronic myeloid leukemia is a rare form of cancer that affects blood cells and is characterized by a genetic mutation between chromosome (9) and chromosome ( 22) known by reciprocal t(9;22) (q34;q11) translocation, Which leads to composition of the chimerical fusion gene (BCR-ABL1) on chromosome (22), which is known after that by (Philadelphia chromosome). More than (90%) of chronic myeloid leukemia patients are diagnosed with presence of Philadelphia chromosome. The present study was carried out on (40) patients who were suffering from Chronic Myeloid Leukemia in Erbil city and (10) healthy individuals as a control group in both sex and different age groups. Blood samples were collected and chromosomal study was performed. The research concluded the effect of several factors, including that most cases were between the age group (41-50) and among males more than females. Also the percentage of illness in relation to the type of occupation was among most females who were housewives at (42%). As for the patients' living location, between inside and outside the city, the result was somewhat close to each other even when taking into consideration the proportion of males and females. As for the occurrence of types of chromosomal aberrations, the study showed that the highest value of chromosomal aberrations was in (Dicentric chromosome), specifically in females of the age group (41-50).