Polyethylene films are a common packaging material. The level and type of chain orientation in these films are a very important property which is of great care and concern of the converter personnel during the conformation process. Usually bi-orientation is the conventional procedure but when easy tear in one direction is needed mono-orientation is sought. This paper deal with the characterization of the crystalline orientation in films of polyethylene blends (HDPE/LLDPE) which have being oriented in two steps: initially the polymer was bi-oriented via extrusion-blown, cooled, and then in a second process hot stretched along the machine direction in order to produce mono-oriented films. Starting from the same blown film different levels of stretching from 2 up to 6 times the original length was applied. The samples were analyzed in a Perkin Elmer - Spectrum 1000 apparatus measuring the infra-red dichroism following the changes in absorption in the 720 cm-1 and 730cm-1 bands. The first band is associated to the absorption of the orthorhombic crystal b axis and the second to the a axis. The film was set with its machine direction aligned with the FT-IR beam polarized in the vertical direction (said 0º). Then, polarization of the FT-IR beam was rotated 360º in steps of 5º by rotating the polarizer. In each step the absorbance spectrum was recorded and the corresponding dichroic ratio calculated after subtracting the baseline. The dichroic ratio was plotted as a function of the angle between the polarization direction of the beam and the mono-oriented film MD. The results show that the c axis is oriented in the MD and the other two axes in the orthogonal direction. The dichroic ratio of both a and b axes increases exponentially with the level of stretching indicating the increase in the level of crystal orientation.