This is a retrospective study based on secondary datacollected during 1990-1994. The objectives of the study were toanalyze the costs to provider in implementing the School-basedOral Health Programme at primary schools in the North of Vietnamwith the aim to suggest the most cost-effective programme. School-based Oral Health Programme has been applied in theNorth of Vietnam since 1985 but the coverage is still low. Forevaluating this programme, dental status is measured by DMFTindices which indicate the number of decayed, missing and filledteeth per person. The effectiveness was measured by thedifference of DMFT index between intervention and noninterventiongroup. In this study, an attempt has been made to analyze thecosts to provider in implementing the Programme and its impactson the dental caries. The analysis consists of three stages: 1. The DMFT indices of the two groups of school children,one implementing the Programme and the other not implementing theProgramme, were tested and it was found that DMFT indices of thetwo groups of school children were significantly different. TheDMFT index of the intervention group was lower than that of thenon-intervention group. 2. By analysing the costs of the programme in the urban,rural area, and two areas, it was shown that by using currentprice and constant price for calculation, the total cost and theaverage cost for running the programme are not too high anddecreased year by year. The Programme is necessary to thechildren in both areas. Under this Programme the children can avoid not only dentaldisease but also related diseases. Besides, they can save moneyfrom dental treatment and save the time loss from their schoolingand their parent's work. From the cost analysis of the programme,cost effectiveness was examined to evaluate the effectiveness ofthe programme. The cost-effectiveness ratio decreased every yearsuggesting that the programme was effective. But this ratio inthe rural area was higher than the urban area. When the Programmewas applied, the effectiveness of the programme in the rural areawas lower than that in the urban area. 3. Sensitivity analysis was carried out to assess theimpact of input activities on the outcome of the programme, givenassumption regarding the change of each component of recurrentcost, which includes consumable cost, personal cost, retrainingcost for the teachers, repair and maintenance cost andsupervision cost. It was found that among these costs, consumablecost played the most important part. This cost had more effect onthe cost-effectiveness ratio when compared with the others. Sensitivity analysis of the change in effectiveness showedthat the change of cost-effectiveness ratio was higher than thechange in the effectiveness. The study provides information about the costs of theprogramme and its impacts but how to expand this programme to anationwide level, it requires a further study.