The potential for contamination of groundwater from subsurface chemical sources poses a risk to the nation's water supply. Monitoring and remediation of contaminated sites have proven to be both technically and financially challenging. Therefore, inexpensive, minimally invasive real-time instrumentation and sensor systems for detecting and quantifying environmental contaminants are needed for characterizing contaminated sites during remediation, and for long-term monitoring at waste sites where remediation is not possible, or economically feasible. This poster described work underway at Boise State University in collaboration with Washington State University to develop a new sensor for detecting gaseous volatile organic compounds (VOCs) present in the vadose zone. A miniature Ion Mobility Spectrometer (IMS) is being fabricated out a novel material – low temperature co-fired ceramic (LTCC). The LTCC material system will allow fabrication of an IMS with superior characteristics (hermetically sealed, higher resolution, smaller size) compared to what is currently possible using conventional fabrication techniques and materials. The IMS system will be packaged in a cone penetrometer housing to allow deployment in the field using direct push techniques. The proposed system is designed for long-term deployment and features wireless transmission of data using cell phone technology. To our knowledge, use of an IMS for detection of subsurface gaseous VOCs has not been previously reported.