The aim of the present work is to study the effect of the addition micro platelets and nano spherical particles of aluminum on the thermal, mechanical, morphological and electrical properties of the PET/PBT/Al composites prepared by melt compounding followed by injection molding. The SEM results showed that the Al particles are uniformly distributed in the PET/PBT matrix. The micro Al seem to be parallel and oriented to the direction of the flow. The crystalline peaks of the blend did not appear in X- ray diffraction pattern due to skin- core structure of PET/PBT blend. FTIR analysis demonstrated that there is no chemical interaction between PET and PBT nor between Al and matrix. The TGA of the Al micro-platelet composites and the Al nano-spherical composites showed that the end of degradation in most compositions shifts to higher temperatures. Analysis of the DSC results revealed that the melt crystallization temperature of Al micro composites and Al nano composites increased by 4 to 14 degrees compared to the neat PET/PBT. The impact strength of Al micro composites increased until it reached the highest value of 53.54 J/m for 3 vol. % which is about 58% higher than that of the neat blend. The tensile strength of the Al nano-spherical composites decreased with increasing Al content. However, the micro Al particles increased the tensile strength of the Al micro composites. This is explained by the good dispersion and excellent interfacial adhesion between the flaky Al and PET/PBT matrix. There is an enhancement in the flexural strength values with increase in the volume fraction ratio of Al powders in the Al micro composites until it reaches maximum value for the sample with 15 vol. % loading. A decrease in the flexural strength was observed for Al nano composites. The flexural modulus of the Al micro composites showed a significant and remarkable results where the flexural modulus rose gradually and reached to 5.66 GPa at highest Al loading of 25 vol. %. The maximum volume fraction of 25 vol. % showed the highest thermal conductivity of 0.561 W/mK which is about 55.61 % higher compared to that of the neat blend. At 25 vol. % the volume electrical resistivity of the composites decreases significantly and a value of 107 Ωcm was obtained which makes these composites a material of choice for electrostatic and dissipative applications. Al-PET/PBT Composites bar did not show much shrinkage or distortion heating at 150C and 200C.