With the rapid development of the electronic information industry, better properties are required for substrate and packaging materials such as high thermal conductivity, low coefficient of thermal expansion, and low dielectric constant. Polymers are ordinarily being used for this purpose due to their high electrical resistivity and low density, but unfortunately they suffer from a disadvantage like low thermal conductivity. To offset this deficiency, adding inorganic conductive particles to polymer is a versatile method. In view of this, the present work aims at developing a class of particulate filled polymer composites with micro-sized aluminum nitride (AlN) particles having an average particle size of 60-80 mu m reinforced in epoxy matrix. A set of composites, with filler content ranging from 0 to 25vol%, have been prepared by the hand-layup technique. Effects of filler percentage on various properties like effective thermal conductivity (k(eff)), coefficient of thermal expansion (CTE), glass transition temperature (T-g), and dielectric constant (epsilon(c)) are studied. It is found that the incorporation of AlN in resin increases the k(eff) and T-g, whereas CTE of the composite decreases favorably. Though dielectric constant of the matrix increases with filler content yet it remains well within the desirable limit. With modified thermal and dielectric characteristics, these composites can possibly be used for microelectronics applications.