The performance of a capacitive probe for soil moisture measurement was studied under laboratory and field conditions. The probe (21-mm ED cylinder) was composed of 2 electrodes connected to an electronic oscillator (38 MHz) located in the probe. Four soils were used to analyse the ’dielectric permittivity-volumetric water content’ relationships under laboratory or field conditions. The sensitivity of the probe including its electronic components in relation to the variations of the temperature (0-45 °C) was very low (< 0.5 permittivity unit). Permittivity measurements were dependent on the quality of the soil-electrodes contact, and on the soil structure near the electrodes. The order of magnitude of the volume of influence was a few cubic centimeters, and the area of the soil most affected by the permissibility measurements was located in the vicinity of the electrodes. The ’dielectric permittivity-volumetric water content’ relationships were linear (r > 0.99), and dependent on soil texture and structure. Moreover, soil temperature influenced the measurements since increases of the order of magnitude of 0.20 permittivity unit per °C could be observed. Permittivity measurements were not sensitive to the concentration of the solution when the electric conductance was < 2-3 mS. Two field experiments were performed using 2 different soil textures. The first soil (C = 10.5%, L = 50.6%, S = 38.8%) was a bare soil, and showed a quite homogeneous soil structure, the second (C = 27.2%, L = 61.7%, S = 11.1%) was cultivated with soybean, and showed a more heterogeneous soil structure. For each experiment field, simultaneous measurements (1 or 2 times per d) of relative dielectric permittivity, soil temperature and gravimetric soil water content were made in the vicinity of the probes (over a 21 and 41 d period, for the 1st and 2nd experiment, respectively). The variation of the relative dielectric permittivity versus time was very similar to the variation of the measurement soil water content. The calibration relationships between the volumetric water content and the relative dielectric permittivity were linear for each capacitive probe. The regression lines for the different capacitive probes exhibited variations between probes, probably due to the spatial variability of the water content, soil structure and/or soil-electrode contact for each sensor. The effects of the soil temperature on the relative dielectric permittivity measurements were similar to the previous results obtained under laboratory conditions, and effects of electrical conductance appeared negligible under our conditions.