A study of the band structure of photonic crystals with a triangular lattice of triangular rods is made using the Plane Wave Expansion (PWE) method. The relative width of photonic band gap is analyzed in terms of geometrical parameters in either Transverse Magnetic (TM) and Transverse Electric (TE) cases for equilateral and isosceles triangular rods. For equilateral rods the size of the triangles and its orientation in the unit cell are the modified parameters, while in the case of isosceles rods the cross area is fixed as the internal angles and the orientation of the triangle in the unit cell are changed. As a result of varying these parameters, band gaps maximums are found for each transverse polarization mode, besides complete band gaps are found.