This study aimed to determine the relationship between melatonin hormone levels, sleep, and factors affecting sleep, psychological resilience, and depression in nurses working with a shift work system. Conducted between February 5-12, 2021, at the Training and Research Hospital in Ağrı province, the descriptive study included 41 night shift nurses and 35 day shift nurses, totaling 76 participants. Blood samples for melatonin analysis were collected and data were gathered using the Sociodemographic Information Form, Epworth Sleepiness Scale, Sleep Disorder Scale Short Form, Brief Psychological Resilience Scale, and Beck Depression Scale Short Form. Melatonin analysis was performed using the ELISA method. Statistical significance was set at p < 0.05. Results showed that sleep disorders were present in all nurses with <7 h of daily sleep. Factors such as the use of sleeping pills, marital status, age, and gender affected sleep disorders. Mean scores for melatonin levels were 67.82 ± 40.20 for night shift nurses and 68.08 ± 39.62 for day shift nurses, with no significant difference between shifts. Similarly, no significant differences were found in daytime sleepiness (7.49 ± 4.47 vs. 7.51 ± 4.65), sleep disturbance (24.71 ± 7.33 vs. 25.23 ± 6.64), psychological resilience (18.42 ± 4.19 vs. 17.89 ± 4.74), or depression (3.22 ± 2.60 vs. 3.49 ± 3.35). Nurses exhibited mild sleep disturbances, low depression tendencies, and moderate psychological resilience. Increased daytime sleepiness and sleep disorders correlated with higher depression tendencies and lower psychological resilience. Hospital management and education units are recommended to conduct interventions on sleep quality, depression, and psychological resilience to raise awareness among nurses.
