Soil and roots associated with different tea clones and nearby weeds (Veronica sp., Setaria sp., Salvia sp., Senecio sp. and Tripogon sp.) were sampled for arbuscular mycorrhizal fungi (AMF) in the tea gardens of Northern Iran. Spores were searched for in the soil and AMF colonisation determined microscopically and fatty acid signatures in roots was determined. Root samples from mycorrhizal and non-mycorrhizal clover were used as positive and negative controls. AMF spores were abundant in the tea garden soils; the genera Glomus and Acaulospora dominated. Microscopic observations of stained tea roots showed no sign of AMF. To confirm this, the roots were analysed for fatty acid signature compounds. The average level of PLFA 16:1 omega 5 as signature molecule for AMF in tea roots was 2 nmol g(-1) dry root, while the NLFA 16: 1 omega 5 was not detectable. In mycorrhizal and non-mycorrhizal clover roots, the PLFA 16:1 omega 5 was 141 and 5.74 nmol g(-1) dry root, respectively. In roots of weeds in tea plantations, the amount of PLFA 16:1 omega 5 was in the range 4.9 to 31.1 nmol g(-1) dry root. Thus, there was no evidence for AMF association in tea roots and weeds are thought to be the source of the spores in the soils. Finally, no mycorrhizal colonisation was found when tea plant seedlings were inoculated with AMF in pot cultures.