本研究旨在探討臺灣1981〜2008年新生兒後期死亡率、新生兒後期各死因死亡率之時間變化趨勢，以及上述指標在不同都市化程度區域變化之趨勢。本研究使用衛生福利部所提供之1981〜2008年死亡檔資料及內政部出生資料進行分析，運用Mantel-Haenszel Chi-Square方法分析新生兒後期死亡率及死因之時間趨勢變化是否顯著，以及探討不同都市化程度區域之新生兒後期死亡率是否有差異。根據研究結果發現，自1981〜2008年新生兒後期死亡率之變化自5.71‰〜1.84‰。1988年後，先天性缺陷為新生兒後期死亡率最主要的死因，約占29%〜32%。新生兒後期死亡率與都市化程度呈負相關，山地鄉的死亡率明顯較高，其次依序為鄉、鎮、市，但整體而言，區域間之差距有隨時間而縮小。所有死因中，僅有突發性嬰兒猝死和與發育未成熟有關的死因占新生兒後期死亡率比重隨時間明顯增加且跨不同都市化程度亦如此，市與山地鄉這期間在與發育未成熟有關之死亡率上升率較高，市與鄉在突發性嬰兒猝死之死亡率上升率較高。意外傷害死因部分，在2002〜2008年間各區域性間仍有顯著差異，值得政府重視。建議未來應深入探討可避免之新生兒後期死亡之相關因素，並研擬降低可避免的死亡率之策略，以縮小新生兒後期死亡率健康不平等之現象。

This study analyzes time-trends in infant mortality, causes of postneonatal mortality (PNM), and differences in PNM based on various levels of urbanization between 1981 and 2008. We used the death data obtained from Taiwan’s Ministry of Health and Welfare and the census data from the Ministry of the Interior for the analysis. The Mantel-Haenszel Chi-Square test was used to test the time trend of PNM and difference of rate ratios among four levels of urbanization. The result showed that the PNM rate had generally declined in Taiwan, from 5.7‰ in 1981 to 1.84‰ in 2008. Congenital anomalies were the first leading causes of death after 1988, accounting for 29% to 32% of deaths. The PNM was negatively associated with the degree of urbanization. It was higher in indigenous areas than in the townships or counties, but in general, the inequality across different urbanization levels was decreasing over time. Sudden Infant Death Syndrome (SIDS) and causes related to immaturity increased over time and became as more important contributors to PNM from 1988 to 2008 across different urbanization levels. This increase was further pronounced over time especially in city and indigenous areas for causes related to immaturity and higher in city and town areas for SIDS. From 2002 to 2008, the area inequalities in PNM related to accidents existed across different levels of urbanization, warranting the attention by Taiwan’s government. It is recommended that future research should investigate the factors associated with preventable postneonatal deaths and develop the strategies for narrowing the health inequalities in PNM across all areas.