Newborn and adult articular cartilage expresses bone (BMPs) and cartilage derived morphogenetic proteins (CDMPs). These morphogenetic proteins act over membrane receptors (BMPRs). We examined the expression pattern of BMP-7, BMP-3, CDMP-1, CDMP-2 and their receptors in adult normal and osteoarthritic, articular, knee cartilage. Immunostaining was carried out using polyclonal antibodies. The expression of BMP-7,-3, CDMP-1,-2 was detected in all layers of normal articular cartilage with the strongest expression in chondrocytes of the transitional layer. BMP-7 and CDMPs expression decreased in osteoarthritic articular cartilage whereas BMP-3 expression was absent. BMPR-IA and BMPR-II were strongly expressed in both normal and osteoarthritic articular cartilage. BMPR-IB was not expressed in osteoarthritic (OA) cartilage. BMPs and CDMPs with intact signalling play an important role in articular cartilage homeostasis, preventing cartilage degeneration.