The objective of this study was to investigate the level of expression of five cytokines in four different articular tissues from the joints of dogs with and without osteoarthritis (OA). Articular tissues were harvested from the stifle (fat, cranial cruciate ligament, synovial membrane) or hip (articular cartilage) from eight dogs with OA secondary to cranial cruciate ligament disease (stifle) or hip dysplasia (hip), undergoing routine surgical treatment for the condition, and from five dogs euthanatized without orthopaedic disease. The mRNA transcript numbers for interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10) and interleukin-17 (IL-17) were determined by quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR). Increased expression of IL-1β, IL-6 and IL-10 in OA synovial membrane, increased expression of IL-1β and IL-6 in ruptured (OA) ligament, and reduced expression of IL-8 in OA synovial membrane were identified. Cytokine expression was detected in multiple tissues within the articular joint, but differential expression in OA was detected primarily in the synovial membrane and cranial cruciate ligament. © 2007 Elsevier B.V. All rights reserved.