In this paper, we present a brief review of current trends in the development of technologies for manufacturing sensors of flammable gases and volatile organic compounds at pre-explosive concentrations. Different types of gas sensor, including catalytic, semiconductor, and optical sensors, and the principles of their operation are discussed. The advantages and disadvantages of each type of gas sensor are shown. New and traditional production technologies of sensitive elements are discussed, providing improvements of sensor parameters such as effectiveness, miniaturization, and reduction of energy consumption. In conclusion, we suggest future trends and prospects for research and development to increase the sensitivity and selectivity of sensors.