Sjögren’s syndrome (SS) is a chronic autoimmune disease that mainly affects the exocrine glands and leads to the sicca complex. There is often a systemic involvement (extraglandular manifestations) and increased occurrence of B cell lymphoma. The pathogenesis of the disease still remains unknown. The current diagnostic/classification criteria for SS are controversial and not universally accepted. The absence of established classification criteria for SS contributes to delays in the diagnosis. In 2003, the Sjögren’s International Collaborative Clinical Alliance (SICCA) was founded to develop standardized classification/diagnostic criteria for SS. To assess the effectiveness of new therapies, in 2007 and 2009, three disease activity indexes were developed: SSDAI (Sjögren’s Syndrome Disease Activity Index), SCAI (Sjögren’s Systemic Clinical Activity Index) and ESSDAI (EULAR Sjögren’s Syndrome Disease Activity Index). The purpose of this review is to summarize current classification criteria and disease activity indexes for SS.