The aim of this study was to investigate the microbial quality of drinking water distributed through water dispenser machines located in schools and universities in Ajman, UAE. In total, 49 drinking water samples were collected from water dispenser machines in the schools and university's premises in the emirate of Ajman. Total coliform and E.coli were detected using Colilert test. P. aeruginosa colonies were counted on Pseudomonas agar using the membrane filtration method. Overall, 25 out of total 49 samples were found to contain either P. aeruginosa, or total coliform or both. Six samples were found positive for total coliform group members, whereas nineteen of the samples were positive for P. aeruginosa. Ten water samples were found positive for both total coliform and P.aeruginosa. P.aeruginosa colonies count ranged between 4 to 51 colonies per 250 ml of water sample. In conclusion, overall microbiological quality of 25 drinking water samples distributed through the water dispenser machine was found unsatisfactory, and this could be attributed to the poor maintenance and improper hygienic conditions of water dispenser machines. In order to safeguard public health, more efforts such as community awareness program, strict regulations such as regular inspections by the local municipalities are needed.Index Terms-Microbiological quality, drinking water, water dispenser.