SpiroSmart is a mobile phone based platform that allows for the analysis of common lung function measures (FEV1, FVC, PEF). By analyzing lip reverberation we are capable of monitoring pulmonary ailments such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. To increase compliance, our target monitoring platform is the mobile phone, a sufficiently small device that is always with the patient. Additionally, we are investigating methods to make the lung testing procedure part of a simple, yet engaging, game on the phone. Home spirometry is gaining acceptance in the medical community because of its ability to detect pulmonary exacerbations and improve outcomes of chronic lung ailments. However, cost and usability are significant barriers to its widespread adoption. SpiroSmart is a low-cost mobile phone application that performs spirometry sensing using the built-in microphone. We evaluated SpiroSmart on 52 subjects, showing that the mean error when compared to a clinical spirometer is 5.1% for common measures of lung function. Finally, we show that pulmonologists can use SpiroSmart to diagnose varying degrees of obstructive lung ailments.