Acid-mediated hydride reduction of tricarbonyl([eta]6-N-methyl-1,2,3,4-tetrahydrocarbazole)chromium(0) affords either the cis-fused exo-hexahydrocarbazole chromium(0) complex {[Cr(C13H17N)(CO)3], (I)} exclusively, or a separable mixture of (I) and the endo-isomer {[Cr(C13H17N)(CO)3], (II)}, depending upon the choice of hydride donor. The conformations of the hexahydrocarbazole systems differ in the orientation of the indoline moiety with respect to the saturated hexahydrocarbazole rings. The isolation of the exo isomer is unusual, as this complex arises via reaction at the sterically more hindered endo face of the coordinated ligand.