OBJECTIVES: To estimate the annual direct and indirect costs of psoriatic arthritis (PsA) in Spain, and to identify key cost drivers. METHODS: : An observational study was undertaken at 18 Spanish centres. Sociodemographic characteristics and duration of the disease were collected from patient hospital clinical records, and PsA-related resources (€, year 2008 values) from patient notebooks. The following direct resources were collected: inpatient hospitalisations, surgeries, outpatient visits (specialists, general care physician, other healthcare professionals and alternative medicine), diagnostic procedures, laboratory tests, medication (prescription -including TNFalpha inhibitors administered at hospital- and non-prescription drugs paid by patients), hospital day-care facilities for the administration of biological therapies and phototherapy sessions. Indirect resources consisted of productivity losses (full or part-time), social assistance and out-of-pocket expenses paid directly by patients (formal caregivers, disease-related investments). RESULTS: Data were available on 287 patients with PsA. The mean age was 52.40±12.53 years, 55.7% were men, and the mean disease duration was 10.85±9.62 years. Of these patients, 24.7% had received biologic therapy during the study period. The average annual cost per patient with PsA was €6710 (95% confidence interval [CI], €4949, €8584). Direct and indirect costs represented €5449 (95%CI, €4367-€6597, 81.2% of total costs) and €1261 (95%CI, €581-€1987, 18.8% of total costs), respectively. The most important categories of costs were for medication (€3,758, 95%CI, €3,338-€4,241, 56.0% of total costs), productivity losses (€1121, 95%CI, €551-€1692, 16.7% of total costs), visits (€750, 95%CI, €507-€943, 11.2% of total costs), and hospital day visits (€306, 95%CI, €289-€324, 4.6% of total costs). CONCLUSIONS: Our data show that psoriatic arthritis is associated with a remarkable impact over society in Spain, with a mean annual cost per patient of €6710. Direct costs represent 81.2% of total costs.