Under clinically relevant conditions such as forelimb training after focal ischemic infarcts, hippocampal neurogenesis in the adult brain is increased (Wurm 2007). Whether neurogenesis is also altered in the course of persistent inflammation, which is associated with long-lasting changes in locomotion, is unknown. Therefore we studied whether rats with a unilateral chronic antigen-induced arthritis (AIA) in the knee joint show an elevated proliferation of BrdU-labeled cells in the dentate gyrus (DG). AIA was induced in 7 female Lewis rats (AIA group). Another 37 animals served as control groups, namely immunized controls with (ICB) or without (ICC) behavioural testing, non-immunized controls with (CB), and without (CC) behavioural testing, and a group with x-ray treatment (CCXray) because locomotor behaviour was also tested using videoradiographic analysis. Forty-two days after AIA induction BrdU-labeled animals were transcardially perfused with paraformaldehyde. BrdU-positive cells were counted ipsi- and contralaterally on every sixth section (40 µm thick) of the whole DG. Both the AIA and the ICB group showed significantly increased numbers of BrdU-positive cells compared to the CC and CCXray groups. The CC and the CCXray groups were not different, and AIA group did not differ from the ICB group. Thus neither X-ray treatment alone, nor immunization alone, nor behavioural testing alone caused an increase of neurogenesis. By contrast, immunization plus behavioural testing as well as AIA and behavioural testing increased neurogenesis in the DG. Thus we propose that behavioural testing in the setting of inflammation may be associated with changes of neurogenesis in the DG.