Two genes HPC/ELAC-2 and AAT were studied in north Indian population. HPC/ELAC-2 was studied in prostate cancer cases and AAT was studied in COPD patients. HPC/ELAC-2 is considered as an important cancer-susceptibility gene in prostate cancer. There are two common polymorphisms of this gene, i.e., Ser217Leu and Ala541Thr. Alpha 1 antitrypsin is a highly polymorphic anti-elastase enzyme, especially active in the protection of alveoli and liver. In the present study, we observed the distribution of two deficient alleles PiZ and Pi S in COPD patients. We extracted the DNA from 157 prostate cancer cases, 200 COPD patients, 170 BPH and 370 healthy controls. The polymorphisms were studied by PCR–RFLP technique. The mutant genotype (Leu/Leu) of HPC/ELAC-2 was present in 9.6, 7.6 and 5.9% of BPH, cancer cases and healthy controls, respectively. Higher risk of Ser/Leu as well as Leu/Leu had shown when compared to healthy controls. That was about 1.5 and 1.7-fold (OR = 1.55; 95% CI = 0.96–2.51; OR = 1.70; 95% CI = 0.74–3.92), respectively. Risk was found to be increased in smokers and those consuming non-vegetarian diet. Our results suggest that the HPC/ELAC-2 polymorphisms, especially in localized cases, could help to predict prostate cancer risk and confirm its high prevalence of the leu/leu allele in north Indian population. Considering heterozygous PiZ genotype, we obtained an OR of 3.82 (P = 0.03). Multivariate analysis adjusted by age sex and drinking habit showed 4.15-fold increased risk for COPD in PiZ heterozygous individuals. No increased risk was observed in the individuals carrying PiS alleles.