The tribological properties of Plasma Nitrided (PN) rings were examined in high vacuum environment (1.6 x 10-4bar) at 25°C, 200°C and 400°C. The high vacuum based pin on disc tribometer was used for this investigation. The two different sliders namely austenitic stainless steel type AISI 316LN (316LN) pin and Nickel based alloy coated (Colmonoy) pin have been used. The tribological parameters such as friction coefficient, wear mechanism and wear rate have been evaluated. The PN 316LN rings exhibits excellent wear resistance against 316 LN pin and Colmonoy pin at all temperatures. However, the PN 316LN ring vs Colmonoy pin pair shows better wear resistance than PN 316LN ring vs 316 LN pin pair. Whereas the untreated 316 LN ring vs 316 LN pin pair exhibits the combination strong adhesion and plastic deformation wear mechanism.