OBJECTIVES: To describe infliximab (IFX) doses and infusion intervals in patients with RA who are anti-TNF naïve or anti-TNF experienced. METHODS: Medical and pharmacy claims for patients ≥18 years with ≥ 2 RA diagnosis codes received January 2000-December 2006 were included from a database of commercial health plans. Patients were excluded for selected inflammatory conditions. Anti-TNF naïve patients had no biologic use for 6 months prior to IFX. Anti-TNF experienced patients had adalimumab/etanercept prior to IFX. Infused doses were calculated by dividing the plan’s allowed amount for each IFX claim by the acquisition cost for a 100mg vial. Results were reported for induction (weeks 0-8), maintenance (weeks 9-52), and one-year (weeks 0-52) periods. Infusion intervals included mean time (days) between infusions during the first year of treatment. RESULTS: A total of 425 naïve (mean age = 53 years; 74% female) and 467 experienced (mean age = 49 years; 78% female) patients were evaluated. The mean IFX dose per infusion for naïve patients was lower during the induction vs. maintenance period (397 mg vs. 455 mg). The mean IFX dose per infusion for one year was 437mg.  Nearly all naïve patients (98.5%) received no more than 8 infusions in the first year.  The mean times between IFX infusions for naïve patients were 19, 29, 56, 57, 55, 52, and 53 days. The mean IFX dose per infusion for experienced patients was lower during the induction vs. maintenance period (428 mg vs. 527 mg). The mean times between IFX infusions for experienced patients were 18, 28, 52, 50, 49, 48, and 41 days. CONCLUSIONS: This observational study reveals IFX utilization differences between anti-TNF naïve and experienced patients. Both naïve and experienced patients had infusion intervals within the recommended labeling.