In the structure of the title compound, [Fe(C5H5)(C6H12N4)-(CO)2]BF4, the arrangement around the FeIIatom corresponds to that of a three-legged piano stool. The cyclopenta-dienyl ligand occupies three coordination sites of the apical position in a n5 fashion, while two CO ligands and one N atom of the hexamethylenetetramine ligand occupy the remaining coordination sites to complete a distorted octahedralgeometry. The asymmetric unit consists of two sets of crystallographically independent cations and anions with the r.m.s. deviations of the overlay of non-H atoms of each pair being 0.081 and 0.120 A ̊, respectively. The Fe—N bond lengths are 2.0459 (15) and 2.0490 (14) A ̊, while the FeCp(centroid) distances are 1.7257 (3) and 1.7246 (3) A ̊. One of the anions displays disorder, with the F atoms having occupancies of 0.58 (4) and 0.42 (4).