OBJECTIVES: To evaluate the emergent care resource enhancement policy by investigating the trend of cross-boundary emergent care (CBEC) flows from 2000 to 2010 among 50 subregions in Taiwan. METHODS: Approximately 2 million randomly sampled representative beneficiaries from the National Health Insurance database were used as the data source. A modified New York University algorithm was applied to classify emergency department (ED) visits into emergent care, as well as ED visits resulting in hospitalization. Subsequently, 50 medical subregions were used as the analytical units to calculate the proportion of CBEC visits between 2000 and 2010 in Taiwan. Paired t tests were applied to examine the differences in CBEC flow over one decade, and the ratio of the third quartile (Q) to the first quartile (Q) was presented to reflect the regional variation in CBEC flow. Finally, the 50 subregions were divided into low, medium, and high groups according to their CBEC flows in 2000, and the differences in the CBEC and emergent care capacities between 2000 and 2010 were compared. RESULTS: The average proportion of CBEC visits nonsignificantly declined from 42.5% in 2000 to 41.2% in 2010. The Q to Qratio slightly decreased from 2.18 to 2.13 in that decade. However, the CBEC flow in the subregions in high CBEC groups significantly decreased, accompanied by a significant increase in emergent care capacity, even when the CBEC rate remained as high as 57.7% in 2010. CONCLUSIONS: Although health policies were designed to increase emergent care resources across subregions, the differences in CBEC flow among subregions did not decrease significantly from 2000 to 2010. Nevertheless, the emergent care in subregions with high CBEC flows improved substantially because of the increase in emergent care capacity. However, the CBEC flow remained high, indicating that allocating more emergent care resources to these subregions is warranted.