Pulmonary function was assessed in non-sensitized male guinea pigs (206-445 g) before and after intratracheal (ITr) treatment with saline or selenium (Se, 0.06 mg/100 g body weight) as selenium dioxide (SeO2) or seleno-L-methionine (SeM). Pulmonary functional parameters such as the respiratory rate (f), tidal volume (TV), dynamic lung compliance (Cdynl) and lung resistance (Rl) were determined using the respiratory flow (F) signal and the transpulmonary signal obtained via the intrapleural pressure (P) from the animal. Although, pulmonary dysfunction was observable with exposure to two different Se compounds, the SeO2-induced changes in f and Rl were significant (P < 0.05). Treatment with SeM did not result in alteration of any of the parameters significantly. Results indicated that acute ITr SeO2 exposure affects respiration precipitated by a significantly decreased f and an increased Rl unlike after SeM. The Cdynl did not change significantly after treatment with either of the two Se compounds. Comparing the immediate effects of the two different Se compounds on respiration, acute ITr SeO2 exposure was found to be more detrimental to pulmonary function than SeM.