Laboratory experiments and full scale tests are conducted to verify and to quantify the advantages of the environmentally adapted oils in hydrodynamic lubrication in terms of operating film thickness, bearing power loss, and operating temperature. Four different oils were studied. Environmentally adapted PAO and ester base ISO VG46 oils were selected from Group IV and V stocks, respectively. Mineral ISO VG68 oil was selected as the reference oil. Mineral ISO VG46 oil was chosen for comparison. Ester base oil provided the best bearing operating characteristics in terms of the developed oil film, pad temperature, and power loss. Thus, it was chosen for the further tests in large full scale bearings. Environmentally adapted ester base oil ISO VG46 provided much better performance than traditionally used mineral oil ISO VG68. Compared to the mineral oil power loss and bearing temperatures are reduced while minimum oil film remains the same. This is an abstract of a paper presented at the 15th International Colloquium Tribology - Automotive and Industrial Lubrication (Ostfildern, Germany 1/17-19/2006).