Background: Spirometry is used to asses respiratory function abnormalities. This is usually in reference to a validated normal range unique to a particular gender, race, age, weight and height. Majority of persons are usually asymptomatic until the expected FEV1 has decreased by 50%. Early intervention on the abnormalities even in this asymptomatic group has been shown to retard the rate of pulmonary deterioration. An unpublished audit at the Aga Khan University Hospital, Nairobi, revealed that majority of newly diagnosed HIV positive persons were admitted at the Critical Care Units with a pulmonary cause which later resulted in poor outcomes. This study explored possible existence of abnormal baseline respiratory function in HIV patients. Objectives: The primary objective was to determine the association between abnormal spirometry and HIV status amongst clients at the Aga Khan University Hospital, Nairobi. Methods: This was a cross-sectional analytical survey comparing prevalence of abnormal spirometry findings across two populations; asymptomatic HIV positive patients and HIV negative subjects. Results: 57%of the HIV positive subjects had abnormal spirometry findings as opposed to 18% of the HIV negative population. 3% of the abnormal spirometry in the HIV population was obstructive airway disease with restrictive and combined constituting 12% and 85% respectively. 64%of subjects with CD4 counts below 200 had abnormal spirometry results. Conclusion: The prevalence of abnormal spirometry findings was higher in the asymptomatic HIV population with worse function for those with CD4 below 200.