Objectives: Malnutrition in patients undergoing hematopoietic stem cell transplant (HSCT) can develop rapidly without appropriate nutritional support and affect morbidity and mortality. Guidance to monitor and manage nutrition status is described within the literature; however, whether this is applied in clinical practice is unclear. Methods: This paper describes a cross-sectional survey to explore current practice approaches in nutrition support management and adherence to international guidelines. Results: A total of 108 nurses from 108 centers across 16 countries replied to the questionnaire. A significant variation was observed regarding the availability of documents supporting the monitoring and management of nutrition status, application of recommendations, and nutritional practices. Discussion: The findings revealed that country was the most important factor influencing the differences in practice; however, significant differences were also observed based on patient age group (pediatrics vs. adults), department composition (hematology + HSCT unit vs. HSCT unit alone), and availability of nutrition health care professionals. Behavioral differences regarding nutritional practice approaches could be indicative of differences in knowledge or subject awareness, as well as a reflection of diversity across health care system policies. Conclusions: Guideline dissemination and raising awareness through educational campaigns are suggested approaches to improve health care professionals’ knowledge and sensitivity to this important topic.