objective. previous researches pointed out the critical changes needed to increase the efficiency of the national screening programme of cervical cancer in mexico. these changes were assessed through a cost-benefit analysis. this paper presents the results of that appraisal. figures are presented as usdollars of 1996 valued as 7.5 pesos for each dollar. results. the operational unitary cost of the integral process of the cytology ？the obtention of the pap smear, its transportation to the interpretation centre, its analysis, and the notification of results to users？ was estimated in us$ 11.6. if the proposed changes are operated, the cost of each citology would increase by 32.7%. the benefit/cost ratio would be 2 and the net benefit of 88 millions of us dollars for the next five years. conclusions. the operation of the proposed changes is socially desirable, but should be supported the training activities of the personnel, the increase of the coverage of women at risk, the quality control activities, the monitoring of the program and the communication with women detected as positive cases.