Background: Cancer colon is one of the most common malignancies which treated by chemotherapy. Cardiotoxicity is one of the most important adverse reactions of chemotherapy, leading to an important increase in morbidity and mortality; it can appear early or late in the course of the disease. Objective: To detect early changes in LV mechanics and to determine if 2D-STE could predict preclinical cardiotoxicity from chemotherapeutic treatment in patients with cancer colon. Patients and methods: The study included 30 patients with cancer colon, age ranged from 36 – 55 years and 20 healthy controls with age ranged from 32 – 55 years. Both groups were matched in age and sex. Clinical evaluation (included full history taking general and local examination) and transthoracic echocardiographic examination (TTE), 2-D speckle tracking echo (2D-STE) were performed to all subjects. Results: 2D-STE showed that apical 2, 3, and 4 chambers longitudinal strain percent as well as Global longitudinal strain (GLS) of the studied patients and controls showed statistically significant difference between controls, pre- and post-chemotherapy. In comparison between control and pre-treatment showed statistically non-significant difference, while comparison between control and post-treatment as well as pre- and post-treatment showed statistically highly significant difference. Conclusion: A substantial impairment of LV systolic function was detecting in cancer colon patients receiving chemotherapy with apparently preserved LV systolic function as evidenced by reduction in global longitudinal strain using two-dimensional speckle tracking echocardiography.