In the title compound, C(18)H(21)IO, the cyclo-hexane ring adopts a chair conformation, whereas the cyclo-pentane ring and the ten-membered tetra-line portions each adopt an envelope conformation. For the five-membered ring, the methine C atom deviates by 0.638 (4) Å (r.m.s. of the four other atoms is 0.005 Å) and for the ten-membered ring, the methine C atom constituting the flap deviates by 0.671 (3) Å (r.m.s. of the other nine atoms is 0.066 Å).