Tribological performances of non-grooved and micro-grooved journal bearings were studied under dynamic loading. Numerous experiments were performed using purpose-built test rig and then simulated using various numerical methods. Friction force, friction coefficient, shaft center orbit, and film thickness were determined experimentally and numerically. The experimental and numerical results were in good agreement and the friction forces progressively increased on plain and circumferential, herringbone, and transversally micro-grooved bearing. The results show that it is necessary to complete detailed investigation about the tribological properties of the micro-grooved journal bearing by taking their shape, depth and operating condition into account. (C) 2012 Elsevier Ltd. All rights reserved.