Abstract: A split sprocket is formed in two opposing half sprocket parts of essentially identical conformation and structure. The halves, when married, form a typical sprocket which may also be a gear or drive pulley. A ring is adapted to engage a circular groove on each side of the sprocket so as to assure the two halves cannot part. A pair of screws also engages the two halves so as to firmly join them. One of the rings may have a cylindrical extension which when fitted into the sprocket adapts the sprocket for being mounted onto a smaller shaft. Each half of the sprocket may be fitted with a tongue and a tongue groove for aligning and maintaining alignment of the two halves.