Background: Breast cancer is becoming the most common cancer among women in both developed and developing countries . Breast cancer has been the leading cause of death among Iraqi women for three decades, and it is the second leading cause of death after cerebrovascular illnesses.Objective: To investigate the epidemiological and clinic pathological behavior of breast cancer in Diyala province.Patients and Methods: A retrospective cross-sectional study conducted at the Oncology Clinic of Baquba Teaching Hospital for 24 months between April 1st and March 31st, 2021. A sample of (257) patients was selected to collect socio-demographic information (age, gender, marital status, history of breast lactation ,history of contraceptive pills, history of breast cancer in family, parity status). Results: The current study shows that more than 55% of the patients were under the age of (50) years. Two hundred fifty one patients (97.6%) were female and( 6) patients (2.4%)were male. from the 251 female patient . Right breast tumor was found in 120 patients (48%) and left breast tumor was found in (127) patients (50.4%) and bilateral breast tumor in (4) patients(1.6%). In terms of breast cancer family history, 28 patients(11%) had a positive family history, while 223 patients (89%) had a negative family history. One hundred fifty seven of patients(63%) had history of breastfeeding and( 94) of patients(37%) had no history of breastfeeding . One hundred forty six patients (58%) had positive history of oral contraceptive pill while 105 patients (42%) had negative history of oral contraceptive pill. twenty two patients (9%) had positive history of smoking while (229) patients (91%) had negative history of smoking . The histopathological result were Invasive ductal carcinoma (I.D.C) in (233) patients (93%) and Invasive lobular carcinoma (I.L.C) in (18) patients. Breast cancer patients were married in 73% of cases, widowed in 13.5 percent of cases, divorced in 2.5 percent of cases, and single in 11% of cases. Most cases belonged to differentiation stage II ( 159) patients (63%), followed by stage III ( 57) patients (23%) , stage I ( 13) patients (5%) and stage IV (22) patients(9%) . Conclusion: The current study concludes that In Iraq, the majority of breast cancer patients were in the second stage, and patients' ages at diagnosis were younger than in other communities. The development and execution of screening programs, as well as the management of risk factors, appear to be critical. Keywords: Breast, Cancer, Patients