Abstract Detection of chemical warfare agents and toxic industrial chemicals using Microfabrication and microelectromechanical systems (MEMS) chemicapactive sensors is described. Our sensor chips consist of 10 parallel plates or interdigitated capacitors with an absorbant dielectric material to measure the dielectric constant of an array of selectively absorbing materials. The dielectric permittivity of these polymer filled chemicapacitors changes upon adsorption and desorption of the chemical vapors. Gaseous analytes including chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) have been exposed to our sensors with the results being displayed and discussed below. Sensor performance was characterized through exposure to various CWAs and TICs over a range of concentrations. The limits of detection (LOD) were determined for several chemicals.