In hospitals, medical instruments are usually cleaned and disinfected in a washer/disinfector. However, it is not efficient for small hospitals or general practitioners to purchase such machines as they would not be working to capacity. We investigated the possibility of cleaning and disinfecting medical equipment in a conventional household dishwasher modified to achieve a temperature of 71 degrees C. For this purpose we contaminated screws with different test soils containing either bacterial (100 screws) or viral (106 screws) suspensions. Test organisms were re-isolated from 2% of the screws after bacterial contamination and 4.7% of those with viral contamination. In both cases we found dishwasher-processing to be a suitable means of disinfecting medical instruments.