Exposure to cigarette mainstream smoke (MS) induces lung inflammation, a key factor in the development of emphysema. Previously we have reported that acute and subchronic inhalation exposure of rats to diluted MS induces changes in inflammatory mediators and greater numbers of neutrophils in bronchoalveolar lavage fluid (BALF) (Vanscheeuwijck et al., 2004; Vanscheeuwijck et al., 2005; Friedrichs et al., in press). Here we report on inflammation and morphometric changes in the lungs of spontaneously hypertensive rats (SHR) following subchronic exposure to MS. The SHR strain is known to be susceptible to cigarette smoke and particle-induced cardiopulmonary alterations (Gilmour et al., 2004) and has been shown to have increased concentrations of MIP-2 and increased numbers of inflammatory cells in BALF following cigarette smoke exposure (Smith et al., 2002). We investigated pulmonary inflammation (cytokines, chemokines, and free lung cells in BALF) and morphometric changes in the lungs.