Purpose: The purpose of this research was to assess the methodological quality of non-randomized studies published in the Journal of Korean Fundamentals of Nursing. Methods: A search of non-randomized studies assessing intervention effects was conducted among all articles published in the Journal of Korean Fundamentals of Nursing between 2011 and 2013. Articles were assessed for quality using the Methodological Index for Non Randomized Studies (MINORS). For each index item, the frequency and percentage of articles meeting the criteria were calculated, along with mean scores by research method, publication year, and research topic. Results: A total of 22 studies were included. The mean score for studies without control groups was 11.75 (range 0-16), and for those with control groups, 19.27 (range 0-24). Results show that improvement is needed on several items: "endpoints appropriate to the aim of the study," "unbiased assessment of the study endpoint," "follow-up period appropriate to the aim of the study," "loss to follow up less than 5%," and "contemporary groups." Conclusion: Although the quality of articles published in the Journal of Korean Fundamentals of Nursing has consistently increased, more emphasis should be placed on using rigorous research methods.