Cancer of the breast is the second most common cancer seen among Indian women. This study describes the use of DHPLC for mutation analysis for BRCA1, BRCA2 and CHEK2 (1100delC) in 22 patients with a family history of breast and/or ovarian cancer and early onset breast cancer (<35 years of age). Three of the 22 patients were found to have a non-sense mutation or a deletion, resulting in a premature stop codon, potentially leading to a truncated protein. Two of these were in BRCA1 (one was a novel 5 base deletion) and one in the BRCA2 gene. No patient was found in our series to have the CHEK2 (1100delC) mutation. DNA from a healthy blood donor and all but one of the 22 patients, demonstrated polymorphisms in BRCA1 and/or BRCA2 genes. This is the first study from South India, on BRCA1, BRCA2 & CHEK2 (1100 del C) mutations in patients with a family history of breast and/or ovarian cancer and early onset breast/ovarian cancer, using the sensitive DHPLC approach.