Background: Cancer medically, is a group of wide range of several diseases which are related with uncontrolled growth process of cells. A cross-sectional study was carried out to assess the concentration of cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) in blood serum samples of cancer patients in comparison with healthy/control subjects.Methods: A total of sixty subjects (30 cancer patients and 30 healthy subjects) were selected for this study from different hospitals of Karachi, Pakistan. Whole blood samples collected, digested and analyzed through graphite furnace atomic absorption spectrometry (GFAAS) for elemental analysis. Results: The results showed that the concentrations of these metals in blood serum of cancer patients were higher than healthy subjects. The mean concentration of Cd, Cu, Pb and Zn were 2.12, 1237.03, 1.87, 1084.74 µg/L respectively. The statistical data obtained was correlated to find the possible interaction between different metals. A negative correlation was observed between Pb/Zn (r = -0.521) in cancer and Cu/Zn (r= -0.431) in healthy individuals. Conclusion: The trend of metals in blood samples of cancer’s patients are as follows: Cu > Zn > Pb > Cd and in healthy individuals are: Zn > Cu > Pb > Cd. The statistical data reveals that there are significant differences found in between healthy and cancers individuals. Regular monitoring study should be carried out to create awareness on metal toxicity.