Al was thermally evaporated onto the conjugated semiconductor polymer, poly(2-methoxy-5,2′- ethyl-hexyloxy-phenylene vinylene) (MEH-PPV) in successive steps. Interface formation and chemical interactions between the polymer and Al were investigated by X-ray Photoelectron Spectroscopy (XPS) and synchrotron source Ultraviolet Photoelectron Spectroscopy (UPS). XPS analyses (angle resolved and sputtering depth profile) proved the formation of an insulating aluminum oxide layer at the polymer metal interface. The C-O bonds in the polymer decreased as more Al was evaporated on the MEH-PPV. Also reaction between Al and the carbon backbone of the polymer leading to the creation of carbon-metal bonds was observed. UPS analysis suggested the possibility of Al reacting with the phenylene ring of the polymer.