In this research natural rubber latex-methylmethacrylate radiation copolymer (KOLAM) were dissolved into base synthetic lubricants (AP-0732 and AP-0733). Physical and chemical properties such as viscosity index, flash point, pour point, shear stability, total base number, sulfated ash content and density have been characterized. The results showed that addition of KOLAM into base synthetic lubricants increased the viscosity index and shear stability of synthetic lubricants (AP-0732 and AP-0733) better than HVI mineral lubricants. Flash point, pour point, shear stability, total base number and density of synthetic lubricant with 1% KOLAM addition conform the document of Ditjen Migas No. 4/K/34/DDJM/1988.