This study evaluated the environmental impact of concrete and concrete structures using artificial lightweight aggregates by comparing the impact with that of normal-weight concrete and concrete structures at the same compressive strength (). The assessment of each environmental impact could be simply formulated as a function of compressive strength and unit weight of concrete. Sand-lightweight concrete and all-lightweight concrete exhibited 43 % and 66 % higher total environmental impact, respectively, for of 24 MPa, and 38 % and 56 %, respectively, for of 40 MPa, when compared with that of normal-weight concrete. The increasing rates relative to the total environmental impact index determined in normal-weight concrete columns, beams, and walls were 6 %, 17 %, and 7 %, respectively, for the use of sand-lightweight concrete, and 23 %, 35 %, and 8 %, respectively, for the use of all-lightweight concrete. The environmental impact of lightweight concrete structures was more significantly affected by high environmental loads of artificial lightweight aggregates than by the section size reduction of structural elements.