Objective: To screen LKB1 mutation in sporadic colon and ovarian tumors. Methods: Using PCR-SSCP analysis, 72 colon cancer, 45 ovarian cancer, 14 granulosa cell tumor were screened for LKB1 mutation. Results: no mutation was in sporadic colon and ovarian adenocarcinomas. Two mutations were detected in one of the granulosa cell tumors: a mis-sense mutation affecting the putative start codon (ATG?ACG, MIT); and a silent change in erxon 7 (CTT?CTA, leucine). Conclusion: LKB1 mutations in sporadic colon and ovarian cancers are rare event and LKB1 is not the target gene lost on chromosome 19p13.3 in ovarian cancers.