Control of mRNA stability and degradation is essential for appropriate gene expression, and its dysregulation causes various disorders, including cancer, neurodegenerative diseases, diabetes, and obesity. The 5'-3' exoribonuclease XRN1 executes the last step of RNA decay, but its physiological impact is not well understood. To address this, forebrain-specific conditional knockout mice (-cKO) were generated, as 1 null mice were embryonic lethal. -cKO mice exhibited obesity with leptin resistance, hyperglycemia, hyperphagia, and decreased energy expenditure. Obesity resulted from dysregulated communication between the central nervous system and peripheral tissues. Moreover, expression of mRNAs encoding proteins that regulate appetite and energy expenditure was dysregulated in the hypothalamus of -cKO mice. Therefore, we propose that XRN1 function in the hypothalamus is critical for maintenance of metabolic homeostasis.