Experimental arthritis is an animal model of chronic inflammation that induces cachexia and skeletal muscle atrophy. It has been previously reported that during acute and chronic phases of the desease there is an increase of muscular protein degradation by the ubiquitin-proteasome pathway. Potential changes in myogenesis during arthritis-induced cachexia have not been studied. The aim of this work was to analize the effect of adjuvant-induced arthritis on markers of muscle regeneration. For this purpouse, arthritis was induced in male Wistar rats by an intradermal injection of Freund’s adjuvant in the sole of the paw. The clinical symptoms of arthritis began 10 days after the injection, and the highest arthritis index was reached on day 22. Arthritic and control rats were humanly killed on days 10, 15 and 22 after the adjuvant injection. In the arthritic rats gastrocnemius relative weight was not modified on day 10, it decreased on day 15 (P<0.01), and it was markedly lower on day 22 (P<0.01). Arthritis induced a marked increase in serum interleukin-6 concentrations and in gastrocnemius ubiquitin ligase muscle-RING-finger protein 1 (MuRF-1) gene expression on all days studied, specially on day 15 (P<0.01). Neither of muscular diffentiation markers myogenin or miogenic differentiator 1 (MyoD) were decreased in arthritic rats. On the contrary, arthritis increased myogenin expression on days 15 and 22 (P<0.01), and MyoD expression on all days studied (P<0.05). Muscular proliferating cell nuclear antigen (PCNA) expression was also increased on days 15 and 22 in arthritic rats.These data suggest that arthritis-induced muscle wasting is mediated by increased proteolysis, but not by decreased myogenesis.