In this study, friction stir processing (FSP) was carried out on AISI 430 ferritic stainless steel with a rotational speed of 1400 rpm and welding speeds of 16, 40, 63 and 80 mm/min by employing a WC-base tool. The X-ray diffraction patterns (XRD) of all samples showed that the martensite phase is formed in processed samples. The results of microstructure investigations illustrated that the grain size was reduced during FSP. Pin on disk wear test was performed for all samples. Maximum and minimum wear resistance was observed in processed sample at a speed of 16 mm/min and base metal, respectively. The worn surfaces of the samples were evaluated by using a scanning electron microscopy (SEM) and an atomic force microscopy (AFM). According to the results, a combination of adhesive wear and delamination mechanism was noticeable in the case of the base metal, and the wear mechanism was changed to the low adhesive wear after FSP. The results also demonstrated that FSP increased the average microhardness in the processed sample at a speed of 16 mm/min. This improvement was attributed to the remarkable grain refinement and martensite formation in the stir zone. To evaluate the corrosion behavior, the cyclic polarization test was performed for the base metal and FS-processed sample fabricated at a speed of 16 mm/min in 0.1 M NaCl + 0.1 M H 2 SO 4 and pure 0.1 M H 2 SO 4 . It was found that FSP deteriorate the pitting corrosion resistance of 430 in 0.1 M NaCl + 0.1 M H 2 SO 4. This behavior was attributed to the formation of martensite in the stir zone and significant grain refinement. keywords: AISI 430 ferritic stainless steel, Friction stir processing, Wear behavior, Corrosion test