The efficacy of 1 % sodium hypochlorite and 2 % glutaraldehyde disinfectant sprays on impression materials (alginate and addition silicone rubber-based impression material) was tested qualitatively and quantitatively for the presence of microflora on untreated (control group) and disinfected impression surfaces after 48 h of incubation using nutrient agar culture medium. Impressions were made of 60 dentulous volunteers aged 20–50 years who were apparently free from medical problems. The colony-forming units (cfu) were counted and compared with the control group. The control group showed growth of viridians streptococci, Streptococcus pneumonia, diphtheroids, and Neisseria. The alginate control group showed more microflora compared with the silicone impression surface of both the control group and the study group. Use of 1 % sodium hypochlorite yielded better results than did 2 % glutaraldehyde.