This study was performed from July to December 1974 to investigate the rates of contamination of distilled water for injection and local anesthetics. 222 vials were sampled from 7 different places of St. Mary' s Hospital The samples were cultured for isolation of microorganisms. The resultswere as follows; 1. Of 222 vials, 11 were Contaminated by 6 types; Staphylococcus epidermis, Bacillus subtilis, Mima polymorpha, Alcaligenes faecalis, Herellea vaginicala and pepto-streptococcus. 2. 5(9.1%) of 55 vials from surgical wards, 2(4.2%) of 48 vials from surgical OPD, and 4(12.1%) of 33 vials from pediotric wards were contaminated. 3. Between rates of contamination of distilled water for injection and local anesthetics and the number of punctures, there was no significant relationship. (CR=1.42 P> 0.1) 4. There was no significant relationship (CR=1.02 P> 0.1) between the rates of contamination of vials and the duration of the first and the last punctures. 5. The ratios of contamination between 75% alcohol and 2% phenol used for disinfection of rubber lids of vials did not show significant difference.