The　growth　direction　of　nanowires　is　critically　important　for　precisely　controlling　their　physical　and　chemical　properties　and　the　performance　of　related　nanowire-based　electronic　devices.　Realizing　the　true　orientations　of　nanowires　is　an　important　issue　regarding　designing　and　growth　of　nanowires　with　desired　orientations　and　the　subsequent　applications.　In　this　study,　we　demonstrated　three　electron　microscopic　techniques　to　determine　the　growth　directions　of　epitaxial　nanowires:　mainly,　correlating　selected　area　electron　diffraction　pattern　and　bright-field　imaging　in　transmission　electron　microscopes,　tilting　the　nanowires　until　their　growth　directions　parallel　to　the　incident　electron　beams　in　scanning　electron　microscopes,　and　correlating　the　nature　of　cleavage　planes　of　the　nanowire　substrates　and　nanowire　projections　in　the　side-view　scanning　electron　microscopic　investigations.