Effects of wear testing temperature and sliding speed on the wear behavior of nitrided and untreated 31CrV3 steel were investigated. The specimens were tested at wear testing temperatures of 25°C and 500°C under a normal load of 15N at a sliding speed of 1m/s. The increase in the wear temperature from 25°C to 500°C led to a decrease in the wear rate and coefficient of friction of the nitrided steel samples. At 25°C, the wear resistance of the nitrided steel improved by 2.3 times compared to the untreated specimen. There was about 57 times improvement in wear resistance as the wear temperature increased to 500oC for the nitrided specimen. Scanning electron micrographs showed that the formation of compact and protective oxide layers on the worn surface of the nitrided steel was responsible for the improvement in the tribological behavior of nitrided steel at elevated temperatures. The effect of sliding speed on the wear of the samples was further tested at 500oC under a normal load of 15N at sliding speeds of 0.5 and 1.5m/s. The results showed that there was higher wear resistance at lower sliding speeds.