Objective: To determine the association of Ki67 with tumor grade and other pathological features in patients with breast carcinoma. Study Design: Cross-sectional analytical study. Place and Duration of Study: Department of Medical Oncology of Jinnah Postgraduate Medical Center, Karachi Pakistan, from Jul 2018 to Jul 2019 Methodology: Two hundred and sixty females diagnosed with breast carcinoma of age more than 19 years were included using non-probability consecutive sampling technique. The histologic grade of tumor has been assessed using the classification of the World health organization. Representative sample was selected from each tumor for immune histochemical staining examination including estrogen receptors, progesterone receptors, Her2neu and Ki67. Nuclear expression has been quantitatively documented for Ki67. Results: The mean age of the study sample was noted as 46.93±12.8 years ranging from 20 to 76 years. Of 260 patients, 17 patients (6.5%) had low Ki67 (1-5%), 23 patients (8.8%) had intermediate Ki67 (6-14%) and 220 patients (84.6%) had high Ki67 (≥15%). The significant relationship was found between Ki67 status and age, stage, tumor size, grade, lymph node status, estrogen receptors, progesterone receptors, HER2/Neu and triple negative (p<0.05). Conclusion: Ki67 index is associated with tumor grade and other pathological features such as stage, tumor size, lymph node status, estrogen receptors, progesterone receptors, HER2/Neu and triple negative.