Infective endocarditis (IE) is a life-threatening infectious disease. Although histopathological examination remains the gold standard for definitive diagnosis, it is performed in only a minority of patients; thus, the diagnosis of IE continues to rely predominantly on clinical manifestations. However, IE presents with highly variable systemic symptoms that often lack cardiac-specific features, posing significant diagnostic challenges. To address this complexity, multiple diagnostic criteria have been developed, integrating clinical presentation, imaging findings, and microbiological evidence. Over the past three decades, substantial shifts in the microbiological and epidemiological profiles of IE, coupled with advances in imaging modalities and laboratory diagnostics, have profoundly influenced diagnostic approaches, driving continuous refinement of diagnostic criteria. This review provides a comprehensive overview of the major diagnostic criteria for IE, traces their historical evolution, evaluates recent updates and diagnostic performance, and offers theoretical insights and practical implications to guide future research.