This tutorial presents a systematic approach to nutrition assessment based on a modern appreciation for the contributions of inflammation that serve as the foundation for newly proposed consensus definitions for malnutrition syndromes. Practical indicators of malnutrition and inflammation have been selected to guide diagnosis that include medical/surgical history and clinical diagnosis, clinical signs and physical examination, anthropometric data, laboratories, dietary assessment, and functional outcomes. Knowledge of systematic nutrition assessment and appropriate diagnosis of malnutrition will help to guide proper interventions and expected outcomes.