This study was aimed to examine the effect of lead acetate on inflammatory biomarkers in blood of guinea pigs in comparison with sensitized animals. Thirty guinea pigs were randomly allocated into control (group C), sensitized (group S), and three Pb-exposed (groups 0.1M Pb, 0.2M Pb and 0.4M Pb). Animal sensitized after aerosolized-ovalbumin (OA) challenge. Pb-exposed groups inhaled 0.1M, 0.2M and 0.4M lead acetate for 1 h, three times a week for two weeks. Total and differential WBC counts, PLA2 activity and total protein levels were evaluated in blood of all animal groups. Serum PLA2 activity, total protein and total WBC number in sensitized and animal exposed to lead were significantly higher as compared to control group (p<0.05). When compared to control group, the percentages of eosinophil, nuetrophil and basophiles were also increased in sensitized guinea pigs (p<0.01). The percentage of eosinophil and basophile in animals exposed to high level of lead and that of basophile in animals exposed to middle lead concentration versus to control group significantly increased (p<0.05). In addition, the significant difference between the lymphocyte percentages of Pb-exposed groups and control group were decreased in concentration dependent manner. The findings of the present study indicated that exposure to inhaled lead acetate may lead to asthma-like disease.