Synovial joint is a hallmark feature of skeletal elements developed through the process of endochondral ossification. During endochondral ossification, mesenchymal cells initially condense to form a contiguous unit of cartilage. The first discontinuity in the otherwise uniform cartilage anlagen arises with the formation of the interzone. Cartilage interzone is a band of flattened tightly compacted cells which is molecularly and morphologically distinct from rest of the cartilage in the developing anlagen. It is at the site of the interzone that the cartilage anlagen segments and eventually leads to synovial joint formation. A synovial joint is a complex, membrane enclosed, fluid filled structure where two adjacent skeletal elements articulate. The articulating surface is covered by a cartilage, referred to as articular cartilage. Apart from the thin articular cartilage layers, the entire cartilage anlagen is ultimately replaced by bone (transient cartilage). Interestingly, cartilage cells of the anlagen differentiate simultaneously into both articular and transient cartilage fates, right next to each other, under the influence and interplay of BMP and WNT signaling. My talk would focus on the earliest events of interzone specification and eventually throw light on how two different cartilage fates are attained simultaneously from a single set of progenitor.