Background <p>Cancer cachexia is a multifactorial illness that has an impact on patients' survival and quality of life. It is responsible for more than 20% of cancer deaths. Despite its high prevalence, there is no evidence-based standard of care for its management. Multimodal treatment and prevention actions are necessary for early identification and management.</p> Purpose <p>The purpose of this study was to identify the prevalence&#xa0;of cancer cachexia among patients with cancer in Jordan and to evaluate the perception, knowledge, and dietary practices that may affect how it is managed.</p> Methods <p>A cross-sectional survey was conducted at one of the main governmental hospitals in Jordan, recruiting 328 oncology patients. The researchers collected data using a valid, previously developed tool for patients with cancer.</p> Results <p>The prevalence of cancer cachexia was 76.5%. Most of the patients, 76.5%, did not know about cancer nutrition, and 93.9% did not know about cancer cachexia. Despite 98.1% reporting preferring to learn from healthcare professionals, 78.7% were not following a compensatory diet, 85.4% were not monitoring weight, and only 4.6% were receiving referrals. Chi-square tests showed significant associations between cachexia symptoms and patients' knowledge and perceptions (<i>p</i> &lt; 0.05). Logistic regression revealed that using a diet, regular weight monitoring, and receiving information from specialists significantly reduced the likelihood of cachexia symptoms (<i>p</i> &lt; 0.05), explaining up to 65.1% of the variance.</p> Conclusion <p>The study draws attention to a significant knowledge gap and insufficient nutrition among cancer patients in Jordan, both of which are strongly linked to the occurrence of cachexia symptoms. Improving cachexia management in this population requires integrated multidisciplinary care, early nutritional assessment, and targeted educational interventions.</p>