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Background and Objectives: Polishing of dental prosthesis prepared in dental laboratories can transmit different infectious agents. These are potential sources of cross - contamination for dental laboratory technicians, dentists and for patients. Non-sterilisable appliances in the dental clinic and laboratory have a health hazard to members of the dental team. The objective of this study was to evaluate the microbial contamination of polishing materials, newly polished acrylic denture and equipment used during the construction of acrylic dentures in dental laboratories. Methodology: Five samples of pumice powder, pumice slurry, rag wheel and sterile gauze swab rubbed on newly polished acrylic dentures were collected from four randomly selected dental laboratories in sterile containers. The specimens were transferred to microbiology laboratory for isolation and identification of bacterial and fungal microorganisms. Results: All specimens collected were contaminated either by bacteria or fungi and both pumice powder and rag wheel specimens were contaminated by 80% of gram positive bacilli and 40% of fungus Aspergillus species. In pumice slurry 100% Pseudomonas and 60% Aspergillus species were identified. The results of this study showed considerable bacterial and fungal contamination particularly in pumice slurry may be due to the use of non-sterile water to mix the pumice powder, Gram-positive bacilli and fungi were present in the samples of pumice powder, rag wheel and polished dentures. Conclusions: Improved sterile techniques in handling dental prosthesis can substantially reduce cross contamination that may occur from the pumice and rag wheel, thereby diminishing the patient's exposure to potentially pathogenic bacteria. [ABSTRACT FROM AUTHOR]