Cancer-related sarcopenia involves extensive muscle degeneration and further complications throughout cancer diagnosis. Sarcopenia concomitant with obesity (SO, sarcopenic obesity) and low bone mineral density (BMD; oesteosarcopenia) intensify poorer health outcomes. The oncology treatment per si and related toxicities exacerbate muscle mass loss. Given the evidence that good nutritional status is essential for alleviating treatment symptoms, and improving overall health and survival, nutritional management is key. Thus, we aimed to highlight in this chapter a broader updated review of the adequate nutritional management for cancer patients with sarcopenia. In cancer, energy requirements can range from 25 to 30 kcal/kg/day depending on patients’ needs and might be restricted for SO patients who may require a higher amount of protein/day. Protein recommendations are between 1.2 and 1.5 g/kg/day and can be boosted by specific amino acids that play a role in improving and maintaining muscle mass. Protein source is also important suggesting a higher amount provided by animal-based food to promote anabolic stimulation. Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) are listed to be beneficial due to their anti-inflammatory effect extended to muscle wasting. Adequate consumption of vitamins and minerals is important for cancer patients with sarcopenia, unnecessary overdoses should be avoided. In particular, vitamin D plays a role in skeletal muscle and BMD maintenance. An appropriate nutritional status for cancer sarcopenic patients can be built on adequate recommendations of energy and macro- and micronutrients varying according to the tumor, treatment, and patient characteristics. Having the body composition measured gives guidance for suitable nutritional management with a more accurate analysis of body components – muscle and fat mass and BMD, and it should be considered for more effective nutritional monitoring and treatment.