Purpose: This study aimed at conducting a case study to compare the differences in reinforcement quantity, sustainability goals, and emissions in a concrete slab between fiberglass reinforcement and steel reinforcement. Method:  To calculate and study the amount of reinforcement and emission values for the different materials, a case study was made on a concrete slab for an industrial single-story building with presented dimensions from the structural engineering company Bjerking AB. Data collection consists of interviews with distributors and employees of the construction department at Bjerking and a literature study. The calculations for minimum reinforcement are valid for both steel and fiberglass reinforcement according to Eurokod 2 and DIBt. Results: Several different factors were taken into consideration including change of parameter values for the separate calculations of steel rebars and fiber glass rebars. The required amount of concrete and emission values for both reinforcement materials of each case was based on calculated minimum reinforcement and on data from climate database of Boverket. The results vary between the different materials depending on the calculated amount of reinforcement which is determined by choice of tensile strength and elastic modulus. Conclusions: A larger amount is needed when reinforcing a concrete slab with fiberglass reinforcement than steel due to higher strain values. The amount of concrete with fiberglass reinforcement is almost equal to steel reinforcement. In relation to the sustainability goals the positive effect of fiberglass reinforcement lie in the difference in emission during production, which is lower than steel.      Keywords: GFRP, FRP, reinforcement, steel reinforcement, sustainability goals, Eurocode 2, CO2e.