In this research high strength structural lightweight mortar with compressive strength in the range of 33.5-52.5 MPa and unit weight in the range of 1625-2105 kg/m3 is produced using perlite as fine aggregate. The current investigation deals with using perlite fine aggregate as replacement of silica sand with different rates. These rates are taken as percentage rates from the sand volume with values 15, 30, 45, 60 & 75%. Compressive strength, flexural strength, modulus of elasticity and unit weight are conducted. The relation between these properties and the percentage of replacing of silica sand with perlite is obtained. The results show that using perlite as fine aggregate and as a replacement of silica sand reduces the unit weight of mortar with linear rate and at the same time producing high strength mortar, which can be used as structural lightweight mortar compared with normal weight mortar.