c-axis-oriented PbTiO3 thin films were grown by sputter-assisted plasma CVD on MgO(100) and on Pt(100)/MgO(100). Highly c-axis-oriented PbTiO3 thin films on both MgO(100) and Pt(100)/MgO(100) had 90 degrees domains in the c-axis-oriented region but had none in the a-axis-oriented region. Lower c-axis-oriented samples had no 90 degrees domains in a- and c-axis-oriented regions on both MgO(100) and Pt(100)/MgO(100) substrates. The higher the c-axis orientation, the larger was the tilt angle between the a-axis of 90 degrees domain in the c-axis-oriented region and the normal to the substrate. This indicates that the axial ratio, c/a, is affected by the c-axis orientation.