Abstract A Monte Carlo simulation was performed on the folding transition of a single stiff polymer chain. We have adapted a polymer model: neighboring beads are connected by a stick and the length of each stick is taken as 1 8 of the Kuhn length. Among the products of the folding from the single chain, the toroidal structure is found to be the most stable. Rod and fused structures between rod and toroid are also generated as metastable states with almost infinite lifetime. These morphologies resemble the experimental structures observed with electron microscopy for the products of collapse from single duplex DNA chains.