A study was undertaken to investigate the effects of whole body chronic vibration on the immune system. Albino rats were exposed to whole body horizontal vibration acceleration 5.0 g, frequency 20 Hz for 3 hours per day for 3 months and changes were observed in plasma corticosterone level, total leucocyte count and differential leucocyte count. Neutrophil functions were accessed by candida phagocytosis and Nitroblue tetrazolium reduction test. The total leucocyte count was significantly decreased. A marked lymphopenia was observed in the differential count of the leucocytes. A significant increase in the plasma corticosterone level, candida phagocytosis and Nitroblue tetrazolium reduction was observed, indicating chronic whole body vibration to be a potent stressor in albino rats. © 2007 Elsevier B.V., All rights reserved.; Medline is the source for the MeSH terms of this document.