Filters play an important role in most RF and Microwave applications. Currently, the electromagnetic spectrum is limited, and the applications are restricted to occupy just a portion of frequency range without affecting the equipment working out of band and also, without being affected by adjacent devices. Emerging applications such as wireless communications continue challenging RF/Microwave filters performance with even more stringent requirements, higher performance, smaller size, lighter weights, and low cost. Depending on the requirements and specifications, filters can mainly be designed with lumped or distributed elements. This paper describes the design of a newly proposed wide band micro strip band stop filter with open circuited stubs.