Aseptic loosening of hip arthroplasties are the main reason for revision operations. Basic research indicates a significant relevance of the interface membrane formed between the implant an the surrounding bone. Their cellular composition and the influence of various factors on the process of aseptic loosening has attracted scientific interest. Cytokines are essential for intracellular communication. Is it possible to reveal differences in the expression profile of cytokines between well-fixed and failed hip arthroplasties using the cDNA array approach? AIM. Generation of a cytokine expression profile characteristic for failed hip arthroplasty. Radioactively labeled cDNA probes were synthesised from mRNA isolated from the interface membrane of six patients with aseptic loosened hip arthroplasty. Using a phosphorimager the analysis of the cDNA arrays revealed nine cytokines which were overexpressed compared with the reference tissue (Calgranulin A, Calgranulin B, IL-10, MCP-1, RANTES, TFDG1, TNFR2, RAI, THYB10). In this study four out of these nine cytokines were found to be connected with the process of aseptic loosening for the first time.