Lung cancer is a leading cause of cancer death internationally, with smoking being the largest single cause. This is the leading cause of cancer death in developed countries and is rising in alarming rates in developing countries. The aim of the present investigation was to measure the levels of malondialdehyde (MDA), a product of lipid peroxidation as supplementary marker in patients with lung cancer. Levels of serum MDA was determined spectrophotometrically in 35 lung cancer patients and equal number of healthy controls. The mean serum MDA level in the lung cancer group was found to be 3.8 ± 2.5 nmol/mL, whereas it was 1.4 ± 0.8 nmol/mL in controls. There was statistically significant increase in serum malondialdehyde levels in the lung cancer patients compared with the control group. The results of this study offer additional data of the association between lipid peroxidation and cancer and should add to the understanding studies in this area for future research. Our observations specify that increased lipid peroxidation levels are associated with cancer development, with and without smoking. Though, an enhanced raise of TBARS in smokers may be due to increased oxidants introduced by smoking.