An electronic nose (E-Nose) has been studied as a means to realize artificial olfaction. Electronic nose “instruments” are currently relatively large, since the signal manipulation and classification are still done by a personal computer (PC) or a laptop. For this reason, we have developed a portable electronic nose system based on a handheld machine by using a vapor detection array made of carbon-black polymer composites and a sensor circuit. In an effort to make a portable electronic nose, we used thin-film chemical sensors based on the carbon-black polymer nanocomposite to reliably detect chemical warfare agents. To replace the large volume of PCs, we used a field-programmable gate array to perform system control, signal manipulation, and classification. This E-Nose system was exposed to dimethyl-methyl phosphonate (DMMP) and dichloromethane (DCM) in parts per million concentration levels. DMMP and DCM were considered as simulants of the nerve agent sarin and the incapacitating agent BZ gases, respectively.