Soil properties and soil water relations were compared between soils of mesquite (Prosopis glandulosa Torr.) dunes and soils of adjacent interdune areas in southern New Mexico. Particle size, bulk density, organic matter content, electrical conductivity, pH, and temperature of dunal and interdunal soils were measured. Except for particle size and temperature, dunal and interdunal soils did not differ greatly. Soils of dunes had more sand and less silt and clay than did soils of interdunes. Soil temperatures were higher in interdunes than in vegetated dunes. Soil temperatures were similar in dunes with plant cover removed and in interdunes. Infiltration and runoff, hydraulic conductivity, and water retention measurements showed that although dune soils had greater infiltration and more rapid hydraulic conductivity, interdune soils retained more water above -1·5 MPa matric potential. Evaporative losses, as measured with atmometers 3 cm from the soil surfaces, were greater from interdunes than from vegetated dunes. Through two growing seasons, measured total soil water content at a depth of 30·5 cm was always greater for interdunes than for either vegetated or bare dunes. The dune soils stored water less efficiently than interdune soils and reached -1·5 MPa matric potential with much greater frequency.