SRD demonstrates microhotplate-based semiconductor metal-oxide (SMO) sensor arrays for the detection of select toxic industrial chemicals and chemical warfare agent simulants with improved reproducibility, sensitivity, and response kinetics. SRD discusses the preparation and gas-sensing properties of nanostructured SMO films microprinted onto microhotplate platforms. The SMO films were deposited onto these platforms using a custom microprinting technique. The microhotplate arrays were characterized using optical microscopy along with electrical measurements during gas testing. The formulation of the nanoparticulated SMO suspensions for microprinting is described. The SMO film characteristics were controlled via the suspension properties and microprinting parameters. SRD's custom microprinting system is discussed along with critical procedural considerations. SRD has evaluated the SMO microhotplate sensor arrays as chemical sensors for detecting ammonia, chlorine, hydrogen chloride, dichloropentane (mustard stimulant) and dimethyl methylphosphonate (nerve stimulant). Key sensor performance characteristics were examined including sensitivity, stability, and response and recovery times. These characteristics, obtained from the microhotplate-based devices, are compared with those obtained from the sensors based on SRD's traditional (i.e. non-MEMS) platforms.