Condition monitoring in the oil industry, especially in harsh environments, often requires robust and reliable techniques. Predictive maintenance (PdM) involves monitoring machine performance by tracking changes in key indicators such as temperature, noise intensity, and vibration levels using specialized equipment. Since the change in some of the indicators is a reflection of the condition shall be deemed aware of the vibration is one of the indicators upon which to build predictive maintenance. Pumps are essential assets in most industrial applications. Historically, maintenance strategies have evolved from reactive (breakdown) maintenance to preventive and, more recently, proactive maintenance, and proactive maintenance. In order to prevent damage and maintain pumps, it is necessary to adopt an suitable system to detect failures before occur. This research demonstrates, through case studies from the Mellitah Complex in Libya, that vibration analysis successfully identified specific faults-including bearing defects, rotor unbalance, and soft foot-enabling timely correct maintenance and preventing costly downtime. This research validated the application of vibration-based condition monitoring for critical rotating equipment at the Mellitah Gas Complex................. Keyword: ................Condition monitoring, Vibration technique, Oil and gas industry, Harsh environment.