2Aims: Ten rhizobial isolates obtained from different locations in Egypt were examined for their ability to survive under stress conditions and their growth response to increasing levels of NaCl (1±8% w/v), pH (4±10), CaCO 3 (1±10% w/v) and 12 antibiotics. Methods and Results: All the rhizobial isolates tolerated a NaCl concentration up to 5% and were divided into two groups with respect to NaCl tolerance. The rhizobial isolates from group two showed signi®cantly (P < 0á05) better survival under high NaCl concentration. All the tested isolates survived acidic (pH 4±5) and alkaline conditions (pH 9±10) and CaCO 3 (up to 10% w/v) in liqued YEM medium. Conclusions: Antibiotic resistance patterns did not correlate to NaCl, pH or CaCO 3 tolerance.Variations among different strains showed that there is potential to improve strain performance under stress conditions. Signi®cance and Impact of the Study: The results suggest that selection of adapted strains under stress conditions is possible and can be used as inoculants for successful lupin growth.