Background:Tumor lysis syndrome is a metabolic derangement which is seen in patients with malignancy and receiving drugs for cancer treatment. It can arise in children or older cancer patients and is considered life threatening. Anticancer drug therapy is most commonly used method to treat cancer. Aim: To investigate the role of electrolytes and vitamins (A, C and E) in cancer patients suffering from tumor lysis syndrome during anticancer therapy. Study design: Prospective clinical study Methods: The study enrolled fifty diagnosed patients of Tumor lysis syndrome.Informed consent was taken from patients.Twenty patients, clinically healthy, age and sex-matched were selected as a control in the present study. 5cc blood was withdrawn from enrolled cases. The obtained samples were centrifuged at the speed of 4000-5000rpm for 10-15 minutes to obtain serum. The levels of Electrolytes (Na+, K+), and Vitamins A, C, E were estimated. Results: Study showed elevated serum levels of sodium (Na+) (28.26) in comparison withcontrol normal persons (21.26) and this is significant statistically (0.02<0.05). Serum Potassium levels among Tumor lysis syndrome (TLS) cases was (13.26) as observed in normal controlled persons (14.26) and results were significant statistically (0.03<0.05). Vitamin A level in Tumor lysis syndrome(TLS) cases decreased outstandingly (102.20) in contrast to normal control study persons.(188.26) and this is significant statistically (0.026<0.05). The values for Vitamin E in Tumor lysis syndrome cases was (4.26) and in controlled normal individuals (7.26) and proved significant statistically (0.015<0.05). Conclusion: Present study showed inverse relationship between Vitamins and electrolytes in TLS. Increased level of electrolyte imbalances and decreased vitamin levels is the reason responsible for the development of tumor lysis syndrome. Keywords: TLS, Vit A, Vit C, Vit E, Na+,K+