Al-Zn-Mg alloys were prepared using RF induction furnace. Two, out of 10 samples were left un-annealed and remaining were given step-aging in temperature range 125-180°C for 2-4 hours. Characterizations of the samples were carried out by using optical microscopy, creep and hardness tests. The results of optical micrographs reveal an equiaxed grain structure formed in all step-aged specimens that becomes more obvious with increase of aging time and temperature. The creep deformation rate was found to be minimum in two step aged specimens, whereas, hardness of the two-step aged samples is maximum as compared to the others samples. [ABSTRACT FROM AUTHOR]