Peri-implantitis has been shown to possess clinical characteristics similar to those of periodontitis. This pilot study was conducted to determine levels of inflammatory cytokines in crevicular fluid from healthy implants and those implants affected by peri-implantitis. Fifty implants from 13 patients were examined. A clinical examination was performed, and gingival crevicular fluid samples were collected and analyzed for cytokines. Implants were categorized clinically as healthy, early peri-implantitis, or advanced peri-implantitis. Interleukin-1ß was detected in the crevicular fluid of implants in all three groups (healthy = 59.47 ± 15.55 pg/site; early peri-implantitis = 460.77 ± 35.67 pg/site; and advanced peri-implantitis = 191.10 ± 21.60 pg/site [mean ± SEM]). These results indicate that interleukin-1ß is present in implant gingival crevicular fluid and may be modulating attachment loss in implants suffering from peri-implantitis. Thus, interleukin-1ß may be used to monitor disease progression. Keywords: crevicular fluid, cytokine, peri-implantitis