The objective of this study was to investigate the state of fatigue and sleep among clinical nurses in Japan. This descriptive cross-sectional study was conducted from December 2015 to January 2016. The participants were nurses who worked in public hospitals with 500 beds in the major cities and regional cities of Hokkaido. Fatigue was quantitatively assessed using the Cumulative Fatigue Symptoms Index (CFSI). Among nurses in their twenties, the rate of complaints about anxiety and decrease in vitality were high, which was replaced with complaints about irritability among nurses in their thirties. The most popular complaint among nurses in their forties was general fatigue. There was no difference in complaint ratios concerning the workplace location among nurses in their twenties and thirties, nurses in their forties working in suburban areas complained about fatigue more than their urban area. Nurses with sleep problems related to anxiety have a significantly higher complaint rate for all the eight items of CFSI compared with the nurses who do not have such problems (p < 0.001). This is an intermediate report and is part of a study that aims to develop a health management program for hospital nurses regarding fatigue and sleep.