Objectives: Defect of basement membrane proteins (BMPs) may be responsible for the separation of the epithelial lining in odontogenic keratocyst (OKC). The purpose of this study was to compare the BMPs including collagen type IV, laminin 1 and laminin 5 of OKC with dentigerous cyst (DC) and radicular cyst (RC). Methods: A standard biotin-streptavidin-peroxidase technique was performed to visualize the BMPs. The primary antibodies against collagen type IV, laminin 1 and laminin 5 were used in this study. Negative controls were omission of the relevant primary antibody. Sections of oral mucosa were stained for being positive control. Results: OKC, DC and RC showed positive reaction to all BMPs. Collagen type IV was expressed in 18/23 of OKC, 21/22 of DC and 17/23 of RC. Laminin 1 was found in 22/23 of OKC, 23/23 of DC and 21/24 of RC. Laminin 5 was shown in 24/24 of OKC, 21/22 of DC and 22/23 of RC. In oral mucosa, collagen type IV and laminin 1 were stained at the junction between the epithelium and the connective tissue and at the periphery of blood vessels while laminin 5 was only detected at the junction. Conclusions: Similar to the oral mucosa, OKC, DC and RC expressed collagen type IV, laminin1 and laminin 5. Difference in the expression of BMPs between OKC, DC and RC was minimal. It is unlikely that the separation of the epithelial lining in OKC is associated with the changes in the BMPs studied. This study was supported by Faculty of Dentistry, Mahidol University research grant.