Burnishing, a plastic deformation process, becomes more popular in satisfying the increasing demands of machine component performance and reliability. Thus, investigating the burnishing parameters in order to improve the product quality is especially crucial. The objective of this research is to study the effect of burnishing process on fatigue life. Experimental work was carried out on a CNC lathe to study the effect of burnishing parameters; such as, burnishing feed and burnishing force, on some surface characteristics such as; surface roughness, microhardness, and reduction in diameter. Then the effects of the burnishing parameters on the fatigue life are investigated through a fatigue test. Burnishing force and burnishing feed play an important role in controlling the values of all surface characteristics and fatigue life. Optimum burnishing parameters are established to minimize roughness and/or maximize surface hardening and fatigue life. It is found that it is possible to get longer fatigue life for machined parts than the virgin material by setting the proper burnishing conditions. Longer fatigue life is achieved using burnishing force of 210 N and feed rate of 0.12mm/rev. In general the microhardness at the burnished surface increases as the force and feed rate increase. The distribution of microhardness along the depth below burnished surface and its affected depth are directly proportional with the burnishing force. It is also clearly shown that the fatigue life of burnished materials cannot be determined or explained solely by surface roughness or microhardness.