Background: Most of previous studies aimed to estimate the effect of nurse staffing on quality of acute hospital care have used stochastic methods and their results are mixed.Objective: To measure the magnitude of effect of nurse-staffing level on increasing quality of acute care services in long-run.Data: The number of practicing nurses' density per 1000 population as the proxy of nurse-staffing level and three Health Care Quality Indicators (HCQI) included 30-day mortality per 100 patients based on acute myocardial infarction (MORTAMIO),hemorrhagic stroke (MORTHSTO) and ischemic stroke (MORTISTO) were collected as a part of ongoing project by OECD.org in panels of 26 OECD countries over 2005-2015 period.Method: Panel data analysis.Results: There were committed relationships from nurse-staffing level to the enhancement of HCQI i.e.1% increase in nurse-staffing level would reduce the rates of patient mortality based on MORTAMIO,MORTHSTO and MORTISTO by 0.65%,0.60% and 0.80%,respectively.Furthermore,the role of nursestaffing level in increasing overall HCQI were simulated at the highest level in Sweden (-3.53),Denmark (-3.31),Canada (-2.59),Netherlands (-2.33),Finland (-2.09),Switzerland (-1.72),Australia (-1.64) and United States (-1.53).Conclusion: A higher proportion of nurses-staffing level is associated with higher quality of acute care services in OECD countries.Also,the nursing characteristics of Sweden,Denmark,Canada,Netherlands,Finland,Switzerland,Australia and United States would be good patterns for other countries to maximize nursing outcomes in the care of patients with acute and life-threatening conditions by reducing the risk of complication,mortality and adverse clinical outcomes.