From July 2000 to July 2001, the hazard analysis and critical control points (HACCP) system was implemented to the benefit of the traditional sandwich production in Phnom Penh City Sandwiches were initially analyzed for bacterial indicators among 6 large-scale producers during a 2 months period. In the second stage of the study, two selected producers were involved in the HACCP process. Microbiological analyses revealed a poor sanitary quality of samples from all the production lines tested. Implementation of HACCP method resulted in a reduction of microbial contamination, but this decrease was not significant compared with others steps of HACCP process (chi2 test for trend, p > 0.05). HACCP system was well accepted by producers but routine practices and wrong perception by production-line workers did limit the success of the process. A regulation on the mass catering sector should be part of a large strategy of food safety and environmental health in the city.