Ancient Greeks physicians already knew the odor of a patient’s breath is associated with some diseases. A non-invasive technology, easy to comprehend and operate, especially for those patients who need everyday monitoring and controls, breath analysis has great application potential for human disease diagnosis. Nanotechnology has provided solutions to overcome the problems with selectivity, sensitivity, response time, and sampling size that have stalled the development of diagnostic breathanalyzes to date. Our group has successfully developed chemoresistive probes that are specific to detecting biomarkers such as NO, ammonia, acetone, etc, though the use of nanostructured metal oxide polymorphs with strong physical or chemical affinity to these metabolites. Furthermore, we demonstrate how handheld breath-collection and analysis devices have been developed to assist with the monitoring of diseases such as asthma and diabetes to cholesterol or cancer. These are extremely promising nanomedicine applications that will improve human health and welfare.