The purpose of this study was to evaluate the effect of Ramadan fasting on fatigue in nurses. The study was conducted between June 19 and July 27, 2014, with a descriptive design. This study was completed with 99 nurses working in a public hospital in the city of Gaziantep located in the Southeastern Anatolia Region of Turkey. The data of the study were collected by using a questionnaire and the Piper Fatigue Scale. The Piper Fatigue Scale includes 4 subscale/dimensional scores and total fatigue scores. Higher scores indicate more fatigue. Statistical significance levels were set at P < .05. It was determined that the fatigue subscale and total mean scores of nurses increased in a statistically significant manner except for the affective subscale after the month of Ramadan (P < .05). In addition, it was found that the fatigue mean scores of those, who were working for 0 to 4 years, were employed in surgery units, and evaluated their health as bad, were higher (P > .05). The Ramadan fasting increased fatigue levels of nurses. Therefore, it is of vital importance to evaluate fatigue levels of nurses especially in the month of Ramadan and take the necessary precautions in terms of patient and personnel safety.