Concrete is a composite construction material made primarily with aggregate, cement, and water. There are many formulations of concrete, which provide varied properties, and concrete is the most used man-made product in the world. Concrete is widely used for making architectural structures, foundations, brick/block walls, pavements, bridges, dams, pools/reservoirs, even boats etc. There is a general view that the size of coarse aggregate affects only the properties of fresh concrete and it is impact on hardened properties is insignificant. This book presents the impact of different sizes of coarse aggregate on fresh and hardened properties of concrete. While slump cone test evaluated the fresh concrete properties, compressive strength test determined the hardened state properties by using concrete mixtures that proportioned with three types of cements. Graded coarse aggregates with maximum aggregate size were selected for this experimental program for each cement. The results show that while the coarse aggregate size influences the slump, it is not relevant to compressive strength. The latter properties are governed by (w/b) ratio, cement type and cement content.