Soil gases have been used as an exploration tool for minerals, oil and gas, and geothermal energy, through the detection of anomalous gas levels. This paper describes a soil gas survey conducted over a large part of the Rotorua geothermal field to supplement the sparse gas data from drillhole samples and to determine gas distribution patterns over the field. Data collected from a reference hole were used to observe the effect changing meteorological conditions had on soil gas levels. The results were inconclusive for CO 2, the only geothermally related gas detected in the reference hole, with the possible exception of changes in atmospheric pressure. 13C measurements made on CO 2 soil gas from an off-field site and three on-field sites (which were expected to contain only geothermally-derived CO 2 ) demonstrated that sites within the geothermal field area can contain CO 2 derived exclusively from a biogenic source. Data collected from the sample sites have been used to construct contour maps to show the gas distribution patterns and downhole temperature range over the surveyed area of the Rotorua geothermal field. An attempt has been made to relate the data to flow patterns in the underground aquifers through a comparison with the interpretations of other studies that were based on geological, hydrological, chemical and isotopic data.