Pear (Pyrus communis), is one of the most important pome fruit in the world, which is cultivated in cold regions. In order to investigate the effect of arbuscular mycorrhizal fungi on osmotic regulators (proine and soluble sugars) and leaf protein in pear seedlings, a factorial experiment was performed with two factors (with and without mycorrhiza) in a completely randomized design with three levels of stress (three, five and seven days intervall irrigation) in three replications on Pyrodwarf tissue culture micro-propagated rootstock in greenhouse conditions. Micro-propagated rootstocks were transferred from glass culture containers to small eight-centimeter pots and were inoculated with mycorrhizal inoculum containing of mixtures of different species and isolates. After two months, the seedlings were transferred to 1 kg pots containing 1: 1: 0.5: 1 (soil: sand: perlite: pit-moss). Six months later seedling transplanted rootstocks were subjected to drought stress for two months. Investigation of mycorrhizal colonization frequency two months after inoculation showed 74% mycorrhizal colonization. final colonization of roots at end of the experiment in one, two and three drought stress levels determined as 84, 81.66 and 72% respectively. After the end of the stress period, the amount of proline, soluble sugars and total protein were measured using spectrophotometer. The results showed that with increasing drought stress, the amount of proline and soluble sugars were increased. With applying of mycorrhizal inoculum, the amount of proline and soluble sugars decreased in all levels of stress compared to non-mycorrhizal treatments, but the protein content were increased compared to the control. Normality error was performed and the results of analysis of variance indicated that there was a significant difference in the mycorrhiza treatments with control at 5% probability level. In conclusion, the results of this study showed that applying of arbuscular mycorrhizal fungi inoculum on micro-propagated roostocks lead to to better adaptation, growthand more tolerance to drought stress.