Purpose: The aim of this study was to evaluate the efficiency of nursing units in a hospital using DEA. Methods: Data were collected using the medical information system of a general hospital in a city. Input variables were number of nurses, number of nurse-aides, number of beds, and overhead costs. Output variables included number of admitted patients, rate of bed utilization, satisfaction of discharged patients, and prevention rate of safety accidents and sores. EMS Window version 3.1 was used to measure the efficiency score and descriptive statistics were applied to analyze the general characteristics of variables. Results: The average efficiency score of 18 general nursing units was approximately .99. Nine nursing units had a 1.00 efficiency score. Conclusion: Our findings reveal that nursing units operated very efficiently. To increase efficiency of inefficient nursing units, we recommend results of the DEA slack analysis as a benchmark of the most efficient nursing unit.