Chronic diseases often lead to metabolic disorders, causing anabolic resistance and increased energy consumption, which result in cachexia. Cachexia, in turn, can lead to major clinical consequences such as impaired quality of life, shortened life expectancy, and increased healthcare expenditure. Existing international diagnostic criteria for cachexia employ thresholds derived from Western populations, which may not apply to Asians due to differing body compositions. To address this issue, the Asian Working Group for Cachexia (AWGC) was initiated. The AWGC comprises experts in cachexia research and clinical practice from various Asian countries and aims to develop a consensus on diagnostic criteria and significant clinical outcomes for cachexia in Asia. The AWGC, composed of experts in cachexia research and clinical practice from several Asian countries, undertook three-round Delphi surveys and five meetings to reach a consensus. Discussions were held on etiological diseases, essential diagnostic items for cachexia, including subjective and objective symptoms and biomarkers, and significant clinical outcomes. The consensus highlighted the importance of multiple diagnostic factors for cachexia, including chronic diseases, either or both weight loss or low body mass index, and at least one of the following: anorexia, decreased grip strength (<28 kg in men and <18 kg in women), or elevated C-reactive protein levels (>5 mg/L [0.5 mg/dL]). The AWGC proposed a significant weight change of 2% or more over a 3-6 month period and suggested a tentative cut-off value of 21 kg/m for low body mass index in diagnosing cachexia. Critical clinical outcomes were determined to be mortality, quality of life as assessed by tools such as EQ-5D or the Functional Assessment of Anorexia/Cachexia Therapy, and functional status as measured by the Clinical Frailty Scale or Barthel Index, with significant emphasis on patient-reported outcomes. The AWGC consensus offers a comprehensive definition and user-friendly diagnostic criteria for cachexia, tailored specifically for Asian populations. This consensus is set to stimulate future research and enhance the multidisciplinary approach to managing cachexia. With plans to develop further guidelines for the optimal treatment, prevention, and care of cachexia in Asians, the AWGC criteria are expected to drive research across chronic co-morbidities and cancer in Asia, leading to future refinement of diagnostic criteria.