The present pilot study examined the effectiveness of self-help therapy (SHT) in hospital nurses in Japan. Twenty-five hospital nurses (22 female, mean age 39.7 +/- 14.6 years) participated in a 90-min workshop covering sleep hygiene education and brief stress management. After the workshop, participants in the SHT group (n = 10) were asked to practice good sleep habits, relaxation techniques, and keep a sleep diary, whereas participants in the control group (n = 15) were not. Pre- and post-test questionnaires, including the Japanese version of the Pittsburgh Sleep Quality Index (J-PSQI), were administered at a 2-week interval to assess subjective sleep quality, sleepiness, depressive symptoms, burnout, and quality of life. Changes in outcomes by treatment conditions were compared using linear mixed models. We found significant improvement in subjective sleep quality (global PSQI scores) in the SHT group, with Cohen's d of 0.40. Participants with sleep problems at pre- test in the SHT group (scoring above the PSQI-J cut-off point) showed significant reduction in sleep latency and sleep disturbance, while those in the control group did not (Cohen's d of 0.48 and 0.15, respectively). No significant improvement was found in the SHT group for sleepiness, although a clinically significant change was observed for subjective sleep quality and sleepiness in this group. No significant improvement was observed in either group for depressive symptoms, burnout, and quality of life. Our results provide preliminary evidence for the effectiveness of SHT for sleep problems in hospital nurses in Japan.