Carbon fiber reinforced composites were prepared using PUI-Epoxy resin as a matrix material and carbon fiber as fibrous material. Similarly, glass fiber reinforced composites were prepared by replacing carbon fiber with glass cloth. Both types of composites were characterized for mechanical and electrical properties and chemical resistances. The poly (urea-imide) was prepared by condensation reaction using an equimolar ratio of an amino terminated oligoimide with various aliphatic diisocyanates. The PUIs were characterized by elemental analysis, the number average molecular weight estimation and thermogravimetric analysis. The cure reaction of an epoxy resin with PUI was monitored by differential scanning calorimetric method.