The use of agricultural tractors for various operations within a day calls for adoption of condition monitoring techniques in maintenance management strategies especially regarding engine lubricating oil change interval and predicting components replacement time before premature failure. Six Fiat tractors from TPU/UPM were monitored over three oil change intervals and oil samples taken for analysis using inductively coupled plasma and optical emission spectroscopy (ICP & OES). Twenty-three elements including wearing elements from engine, additive elements from oil manufacturers, and contaminating elements from the environment were determined from 39 samples collected. Results indicated significant differences for 15 elements (Al, B, Ca, Cr, Cu, Pb, Mg, Mo, P, Ti, V, Zn, Si, K, and Na) belonging to wear, additive, and contaminating sources. This necessitated the use of condition monitoring for individual tractors instead of the general rule of preventive maintenance or even breakdown maintenance performed after the occurrence of failure.