Thin films of tetrathiafulvanene–tetracyanoquinodimethane (TTF‐TCNQ) grown on mica substrates by vacuum deposition were studied by scanning tunneling microscopy (STM). STM images displayed the usual arrangement of alternative TTF and TCNQ columns aligned parallel to the crystalbaxis. However, in addition to the same phase as that of a TTF‐TCNQ bulk crystal, a new phase is observed. In this new phase the tilt angles the TCNQ and TTF molecular planes make with thea×baxis are different from those observed in the normal phase. This new phase can be explained by the introduction of a stacking fault on the surface. ©1995 American Institute of Physics.