OBJECTIVES: To determine the co-morbidity and direct cost influence in patients with osteoporosis in a Spanish population setting in under usual medical practice. METHODS: We performed a transversal retrospective study realized beginning from registers of subjects older than ≥44 years appertaining to seven centers of primary care (year 2,006). A control group without osteoporosis was formed. Main measures: general (age, gender), general co-morbidities and specific (ICPC-2), Charlson index (patient severity), biochemical parameters (lipids, glucose, etc.) and cost model. The general morbidity charge was quantified beginning from Adjusted Clinical Groups (http://www.acg.jhph.edu). The program provides the utilization bands of resources (RUB, co-morbidities levels). It was considered fixed/semi-fixed cost structure/salary/services) and variable one (diagnostics/therapeutical requests, referrals, drugs). Logistical regression analysis was effected (procedure: enter) and the covariance (ANCOVA) for the correction of the models (procedure: Bonferroni), according to the recommendations of Thompson-Barber. Program SPSSWIN; p<0.05.    RESULTS: A total of 35,207 subjects ≥44 years were studied, 10.9% (95% CI: 13.3-15.1%) show osteoporosis (average aged: 62.5±11.8 years; woman: 94.4%). The patients with osteoporosis presented main general morbidity (RUB: 2.9±0.6 vs. 2.7±0.7; episodes: 8.0±4.5 vs. 5.7±3.7), total cholesterol (213.2±36.1 vs. 208.9±30.9 mg/ml), visits (12.9±10.9 vs. 9.6±9.3) and polypharmacy (41.2% vs. 22.2%), p<0.001. The osteoporosis had an independent association in presence from fracture (OR=1.4), fibromyalgia (OR=1.3), dyslipidemia (OR=1.3), asthma (OR=1.2), depression (OR=1.2) y thyroid diseases (OR=1.2), p<0.001. The average unitary/total cost adjusted for year, gender and RUB was €1387.28 vs. €808.98; and the pharmaceutical of €1018.62 vs. €522.33; p<0.001. All components of outpatient management costs were significantly higher in the osteoporosis group. Eighteen percent of the total cost was related to drugs. CONCLUSIONS:Patients with osteoporosis presented a high morbidity (general) and specific one, existing differences of gender (women), producing a high consume of sanitary recourses.