OBJECTIVES: The European Medicines Agency (EMA) and the United States Food and Drug Administration (FDA) have different regulatory systems for the review and approval of new drugs. This study reviewed and compared the characteristics of priority review new pharmaceuticals (i.e. new molecular entities -NME- and new therapeutic biologics -BLA-) approved by EMA and the FDA in the period 2006-2011. METHODS: Data were extracted from the FDA and EMA websites. Dates of application and approval and orphan status information were extracted from the FDA approval letters and the EMA public assessment reports. Descriptive statistics were used to compare the approval processes and characteristics of both systems; t-test was used to assess differences in average review time. Significant level was set at 0.05. RESULTS: A total of 47 drugs (34 NME and 13 BLA) were approved by both regulatory agencies in the study period. BLAs were submitted to the FDA 22±166 days earlier (median=10 days) and approved by the FDA 211±145 days earlier (median=168 days) than the EMEA. NMEs were submitted to the EMA 229±832 days earlier (median=33) and approved by the EMA 97±884 days earlier (median=173 days) than the FDA. The average review time was statistically significantly lower (p<0.001) for the FDA 258±200 days (median=184 days) than for EMA 406±96 (median=407 days). The number of products with orphan designation at the time of the first approval was higher in the FDA (n=20) than in the EMA (n=15). EMA granted orphan designation at the time of approval to two products that did not have orphan designation in the US. CONCLUSIONS: There are significant differences in the time elapsed between the filing and the approval of priority review products in the US and EU. Orphan designation also varied between the two regulatory systems. Harmonization of the regulatory systems could facilitate timely approval of essential pharmaceuticals.