Study of the quality of commercial bottled mineral waters in Malaysia is a study to investigate the water quality constituents in the most common commercial bottled drinking waters in Malaysia. There had been lack of reports on analysis of drinking bottled water in Malaysia, mostly were dispersed and not fully documented. Thirteen brands of bottled drinking waters consisting of both purified and mineral types were collected from different area in Kuala Lumpur and evaluated for their fitting for human consumption. The water quality constituents analyzed include alkalinity, chloride, conductivity, fluoride, total hardness, Al, Cd, Co, Cu, Mn, Pb, Zn, nitrate, pH, phosphorus, sulphate, total dissolved solids and turbidity. The results acquired were compared with WHO?s Guideline for Drinking Water Quality. The discoveries made by this study also shown that most commercial bottled mineral waters in Malaysia had not meet WHO's Guideline for Drinking Water Quality, although they were stated otherwise. There were also slight contrast in quality of the bottled mineral waters and purified bottled waters for those who concerned about their health and the consumption of bottled water.