Trueness and precision of a method for determining the water content (%) of food and chemical products based on infrared radiation with a wavelength in the range (2.70÷7.21 μm) was evaluated. The most accurate measurements for food products were obtained when the heat source was a radiant heater with a radiation wavelength of 7.21 μm, a trueness deviation of 0.01%. When heated with radiation with wavelengths (from 3.32 μm to 7.21 μm), the trueness of the measurement ranged (0.03% ÷0.13%) for chemical products. The shortest analysis time for food products was found when the analysis was carried out using an IR source with a wavelength of 7.21 μm, while for chemical products, a heat source with a wavelength of 2.70÷7.21 μm was optimal. According to the results of the analysis, the use of IR radiation with a wavelength range of 3.32÷7.21 μm is an alternative for accurate measurements.