This study was planned to determine the happiness level of nurses. The population of this descriptive study was done with 121 nurses who accepted to participate in the study out of 323 nurses who worked at a research and training hospital. The average happiness score of the nurses is 108.63 +/- 19.48. However, the mean scores of happiness scale of nurses who had an average working time of 120-180 hours per month and who were satisfied with nursing and working in the institution were higher (p < 0.005) and these findings were statistically significant. In conclusion, nurses' happiness level was found to be higher than the average level (moderate level). But, it was identified that nurses who did not exceed weekly working hours were happier and nursing not being satisfied with working in the institutional negatively affects the level of happiness.