Biodegradable environmentally friendly lubricating greases are used in many technical applications such as friction pair rail-wheel ledge; open rail-road mechanisms; bearings in railway and tram wheels; open gears and axles in agriculture and digging machines; mechanisms in boats and domes; even food industry applications where direct contact with food is unlikely and greases have no toxic substances.  The choose of lubricating grease should be made according its consistency, interval of operating temperature, mechanic stability, resistance to temperature fluctuation, water hydrolysis and, oxidation resistance, corrosiveness, re-greasing interval, lubrication properties and suitability with the environment. The operating conditions such as sliding or rolling speeds, contact pressure and its applying method, thermal and environmental conditions are critical [1].  During operation or even storage the lubricants tend to oxidize. This is especially important for biodegradable lubricants. Oxidation of lubricating greases can be easily observed by change of color, degradation of thickener structure which leads to oil separation. The rise of acidity and viscosity can be observed with the aging of the biodegradable lubricants. Those changes will influence tribological properties and corrosiveness of lubricating greases [2, 3].  The rate of oxidation is influenced by operating or incident temperature, presents of humidity, metal catalysis. It is generally considered that temperature has critical impact on oxidation rate – increasing the temperature by 10 °C the oxidation rate can rise twofold [4, 5].  In this study the tribological properties and corrosiveness of fresh and oxidized lubricating samples are investigated. All the properties are discussed and the role of interacting surfaces is evaluated.