OBJECTIVES: To compare health care utilizations between patients who switched from a branded proton pump inhibitor (PPI) to a generic PPI and vice versa. METHODS: We conducted a retrospective database analysis using commercial enrollees from a large US health plan from February 2008 to March 2010. Continuously eligible adult patients who had gastroesophageal reflux disease (GERD) or GERD-related conditions, and evidence of PPI use during February 2009 to September 2009 were included. The index PPI was defined as the first PPI prescribed during the identification period. Patients who switched from a generic PPI to a branded index PPI and patients who switched from a branded index PPI to a generic index PPI were included as the two cohorts in this study. Risk adjustment was performed using propensity score matching.  We controlled for age, gender, region, GERD severity, plan, pre-index Quan-Charlson comorbidity score (CCI), baseline DACON, and baseline costs and utilization. RESULTS: A total of 9881 patients from each cohort were matched after propensity score matching. During the six months after the switch, there were no significant differences in office visits, emergency room visits, and inpatients admission rates between the two groups of switchers. Patients who switched from a branded PPI to a generic PPI had a slightly lower rate of outpatient visits compared to patients who switched from a generic PPI to a branded PPI (54.67% vs. 56.23%, p=0.0275). CONCLUSIONS: Although outpatient visit rates were slightly lower for patients who switched from a branded to a generic PPI, there were no significant differences in other health care utilizations such as office visits, emergency room visits, and inpatient admissions.