OBJECTIVE Compare the cost-effectiveness of self-monitoring of blood glucose (MBG) with your non-use. METHODS Descriptive and retrospective study covering the period 1995-97 in the 597 type-2 diabetes patients: 286 practicing MBG on a stable basis and 311 not doing so. All are registered in seven health districts in the territorial ambit of Tortosa Primary Care. Were quantified the direct costs in relation to consumption of reagent strips for the practice of MBG, outpatients visits in your primary care center, derivations to specialist of reference and complementary test according to recommendations of the European NIDDM Policy Group in the population user of MBG and no-user; the annual cost increment, the average annual cost and the total annual cost in the population user of MBG and in the application of a ideal model of quantitative and qualitative cover according to clinical recommendations of the Gedaps; and the cost-effectiveness. RESULTS While the 78% of the total diabetic population satisfy some clinical indication for prescribing MBG, only the 42.5% practice the MBG. The consumption of reagent strips rising of 8% to 15% of the global cost of the diabetic population. In the application of the ideal model of cover, this cost increase up the 30% of global cost. The effectiveness obtained, an 27%, not are significantly different in the population user of MBG and no user. The cost-effectiveness in the user of MBG increased of 210.789 ptes/year to 213.148 ptes/year; and no-user of 162.019 ptes/year to 162.051 ptes/year. The application of ideal model of cover and the gain of an effectiveness near to possible level of efficiency imply an descent average of cost-effectiveness of approximately 60%: 78.904 ptes/year in user MBG and 54.682 ptes/year in no-user. CONCLUSIONS 1. We choose in the presents conditions the option of no-user MBG. 2. The average cost-effectiveness per diabetic patient will increase by the needs of accommodate the therapy to new standards of metabolic control. 3. Are clear opportunity for the improve the management and to motivate an efficient use of technology associate to defects of public sanitary market. 4. The model of ideal cover associated to greater effectiveness are necessary for to unify the economic and clinic efficiency.