It is widely accepted that although bacteria are initiating agents in periodontal diseases, the host response to the pathogenic infection is critical for disease progression. The host inflammatory response to bacterial infection involves the production of a variety of humoral factors and their release into surrounding tissues. Despite increased understanding of the etiology and pathomechanism of periodontal diseases, the diagnosis and classification of these conditions are still almost entirely based on traditional clinical assessments. This diagnostic procedure is inherently limited, in that only disease history, not current disease status, can be assessed. Therefore, there is a need for the development of new diagnostic tests that can detect the severity of disease, predict future disease progression, and evaluate the response to periodontal therapy. Nowadays it seems that quantitative and qualitative analysis of specific constituents in gingival crevicular fluid (GCF) can be useful for the evaluation of periodontal health status. Taking into account that cytokines are central to the pathogenesis of inflammatory processes, including periodontal diseases, in this review the authors discussed the usefulness of cytokine level evaluation in GCF for periodontal disease diagnosis. The authors described proinflammatory cytokines, such as interleukin (IL)-1 beta, IL-18, IL-6 and tumor necrosis factor (TNF), some chemokines, that is IL-8, RANTES and monocyte chemoattractant protein (MCP-1), as well as anti-inflammatory cytokines such as IL-10 and IL-4