The authors theoretically demonstrate a plamonic beam deflector based on the particular properties of surface plasmon polaritons in metallic nanoslits. Beam deflection ranging from 0 degrees to 90 degrees can be achieved by designing the deflector with appropriate structural parameters. Numerical illustrations of deflectors for variant deflection angles are presented through finite-difference time-domain simulation, showing good agreement with theoretical analysis. The efficiency and some factors influencing the deflection behavior are also discussed. (c) 2008 Optical Society of America.