Mycorrhizal infection and its consequences were assessed for Agave deserti Engelm., Ferocactus acanthodes (Lem.) Britton & Rose, and Opuntia ficus–indica (L.) Miller. For A. deserti and F. acanthodes in the field, mycorrhizal infection varied from 2 to 11%; the higher infection in May than in March 1991 was probably associated with improved soil water conditions. Using field–collected fungi, mycorrhizal infection for glasshouse–grown A. deserti, F. acanthodes and O. ficus–indica varied from 8 to 64%, with the highest infection occurring for lateral roots of A. deserti. Five months after inoculation, root P was significantly higher (P > 0—-01) for inoculated A. deserti and shoot P and Zn were significantly higher (P < 002) for inoculated A. deserti and F. acanthodes compared with uninoculated plants. Root hydraulic conductivity (Lp) of lateral roots of A. deserti was 24% higher for inoculated than for uninoculated plants (P 01). The increase in Lp was caused by a higher radial conductivity, which could be due to increased root cell membrane permeability and more hyphal entry points. Daily net CO2 uptake was 19% higher for inoculated than uninoculated A. deserti. Mycorrhizal infection apparently enhances water and nutrient uptake in dry environments for these three desert succulents.