Globally, gram-negative bacteria are a significant cause of morbidity. Multi-drug resistance bacteria are responsible for an increasing surge in infections that place a high cost on healthcare systems around the world. Recently, colistin, an antibiotic belonging to the polymyxin family, was reintroduced to combat multidrug- resistant gram-negative bacteria. Excessive and persistent use of colistin has led to the development and spread of colistin-resistant gram-negative bacteria throughout the globe. Healthcare units in various countries, including Saudi Arabia, are currently battling colistin-resistant gram-negative bacteria. Recently, colistin-resistant gram-negative bacteria have become a major health concern in Saudi Arabia. Hence, extensive epidemiological surveys and studies are required to understand the current status of the colistin antibiotic. Examining the knowledge currently available to the medical community on the molecular mechanism, clinical effectiveness, molecular epidemiology, and bacterial resistance to colistin in Saudi Arabia is the aim of this review.