A B S T R A C TResearch on increasing the buckling strength of tanks carrying fluid and also cylindrical shells of thinwalled steel in civil engineering and mechanics is important. This is due to the widespread use of these structures in the industry. Due to the low thickness of the body and also due to the pressure forces entering these tanks, these structures are exposed to lateral buckling. In this research, the use of Carbon Fiber Reinforced Polymer (CFRP) rings to enhance and increase the buckling strength of tanks has been investigated. For this study, a tank with dimensions close to the actual tanks has been built and reinforced by a CFRP ring against the buckling. The results of the experiment indicated that the use of CFRP reinforcing ring considerably enhanced the buckling and post-buckling capacity of the tank. Further, comparing the results obtained from the experimental and numerical analysis and the values extracted from the theoretical relationships suggested that the results are in good agreement.