New systems have emerged for diagnosis, staging and response assessment in multiple myeloma (MM). The diagnostic and response criteria recommended are primarily derived from the International Myeloma Working Group, with certain updates and clarifications. The International Staging System is the current standard for staging of myeloma. A new risk stratification model is provided to specifically define high-risk patients who may benefit from novel therapeutic strategies. This paper provides the current criteria for diagnosis, staging, risk stratification and response assessment of MM.