What are the differences between Concrete structure and Steel structure? And for what purposes is it better to use concrete or steel structures? Concrete is the second most used material for construction after water in the world. Concrete is widely used in today construction industry because of its durability and compatibility. It can be mounded in any shape which makes it a very useful. In addition to the unique aesthetics achieved with concrete construction. Steel has the highest strength-to-weight ratio of any construction material. steel used for making construction materials in a variety of shapes. Many structural steel shapes take the form of an elongated beam having a profile of a specific cross-section. Structural steel shapes, sizes, chemical composition, mechanical properties such as strengths, storage practices, etc., are regulated by standards in most industrialized countries. It’s a very flexible material in terms of different ways to address design requirements. The aim of this paper is to compare between concrete structure and steel structure and show differences between them. There are three fundamentals metrics to highlight the comparative differences between concrete and steel structures: design, function and application, and overall performance.Firstly, in civil engineering, each design is made for specific tasks. So as for Concrete and steel structures (CS & SS) both have various designs that are made for unique uses. Gupta (2017) mentioned that there are many ways of making CS designs that have a lot of uses in the field. This clearly indicates that reasons of wide spirit uses for CS in different constructions as for example plain cement concrete which is a mixture of cement, sand, rocks, and water in specific proportion is used in streets, residential blocks, walls, etc. and this because it can carry compressive than tension strength. Another example is reinforced cement concrete, due to its low-tension strength it is reinforced with steel bars inside it to carry more tension force and its uses are in building, flyovers, water tanks, etc. on the other hand, SS has also its own designs that allow them to do specific tasks. According to Brakefield (2017) and El-Reedy (2013), there are many designs of SS that make the widely used in various constructions. An example of this point is angle beams which take L shape and they are used in floor system to reduce structural depth, in addition to bearing pile which take H shape and it is suitable for deep foundation system as it can carry load more than 1000 tons of weight also there are channel beams which are like C shape and they are used in bridges and marine piers. These types of several designs allow engineers to have multi options for choosing the right design for the specific.Secondly, CS and SS have wide application in the field. These applications are mainly used in our daily lives. Happho (2016) has mentioned that CS has wide range of applications. What interested about this point is that CS is involved in most of constructions civilian, military and …. etc. For instance construction of floor and roof slabs, columns and beams in residential and commercial structures, bridges of small, medium, long spans resulting in aesthetically superior and economical structures in comparison with steel bridges, Pisa tower, and Hoover Dam. On the opposite side, SS have also lots of application that let them to be the most used nowadays. According to Happho (2016) and Jamal (2017), they have mentioned that SS is most often used in constructions that can carry load of both compressive and tension strength. This is a surprising evident as this is one of the advantages of SS and that why they are used in high rise building, industrial buildings, residential buildings, Eiffel tower, The Geodesic Dome at Walt Disney World, 20 Fenchurch skyscrapers in London and Shukhov tower in Russia. These applications show the durability and powerful and how can we depend on CS and SS in many different constructions.Finally, it is evident that concrete and steel structures have various performances between each other. Each structure has its own performance that qualifies it for specific tasks, for example, concrete structures have advantage x, so this construction is mainly dependent on using concrete structure because of x feature. Happho (2016) pointed out that concrete and steel structures both have advantages in overall performance that make them two of the most important structures uses in civil engineering in many types of constructions. This is valid point since these advantages allow the constructions processes much easier to be handled for instance as for concrete structures no excessive maintenance is required in comparison to steel structures and it can tolerate high temperatures from fire for a long period of time without losing structural safety while for steel structures, less time to build than concrete structure, ease to expand the structure, wide range of joining methods like bolting and welding , they are more flexible than concrete that let them to have high dynamic forces resistance like wind or earthquake forces and they can take up both compression and tension forces . On the other side in real life there is nothing is perfect so there are disadvantages in performance for both structures. According to Happho (2016) and Madsen (2005), the two structures have some disadvantages that might delay the process of the constructions. The author has a point because these disadvantages are like an obstacles in constructions process to illustrate the main disadvantages for concrete structure are high dead weight that makes them less used in high-rise buildings, as more load will be there on the foundation, concrete can take up high amount of compression force but is not good enough for tension force while as for steel they are costly compared for concrete, they are prone to corrosion in humid or marine environments that is why they need consistent maintenance and they need more time for design compared to concrete.To Conclude, this paper is mainly talking about the comparative differences between concrete and steel structures from design, functions, and overall performance. It is obvious that concrete and steel structures are like water, we cannot leave without them. We need them in our daily lives in constructions like hospitals, schools, houses, restaurants, stadiums, military, business towers and everywhere around us. So, experts in civil engineers may try to develop these structures, try to enhance CS and SS abilities for better and to overcome their disadvantages.