ABSTRACT Background: Behavioral characteristics of living organisms may affect the metabolism and its underlying molecular basis. The lifestyles of some modern communities include prolonged light exposure at night, and a high-fat/high-sugar-containing diet is frequently investigated. The molecular mechanisms of this unhealthy behavior might involve Adropin and some related nuclear receptors. Aim of the Study: Long-term continuous light exposure (CL) and western diet (WD) effects on Adropin expression, RORα, and Rev-erb-α nuclear receptors and energy homeostasis were studied in rats. Material and methods: Thirty-two male Wistar rats (250–290 g) were enrolled for 3 months in the following groups (n = 8/group): (a) Normal control group (NC), (b) CL group, (c) WD group, and (d) CL + WD group. Then, indirect calorimetry and food intake (FI) were measured. Finally, Adropin, hormone-sensitive lipase (HSL), adipocyte triglyceride lipase (ATGL), and free fatty acids (FFA) were measured. Additionally, the histopathology and gene expression of Enho, RORα, and Rev-erb-α genes were done. Results: The CL alone elevated the Adropin plasma level and gene expression, increased ROR_α expression, and decreased the Rev-erb-α nuclear receptor expression mainly in the liver and kidney. Besides, CL increased the total energy expenditure (TEE) and decreased the respiratory quotient. WD alone or in combination with the CL reversed gene expression of Enho, RORα, and Rev-erb-α. Combined CL and WD increased the TEE, reduced the food intake, increased the ATGL, and reduced the Adropin level in addition to widespread degenerative changes in the liver, spleen, and renal tissues. Conclusion: The deleterious effects of CL and WD on energy homeostasis may include Adropin with the involvement of the RORα and Rev-erb-α nuclear receptors. Keywords: Adropin; continuous light; Western diet; ROR α; Rev-erb- α; energy expenditure