This experiment was performed to isolate and characterize Azospirillum present in Egyptian soils. Intrinsic antibiotic resistance against 11 antibiotic were determined. The ability of Azospirillum introduced as seed inoculation, to survive in soil and to colonize the rhizosphere was tested. Wheat, Faba bean and Squash grown in clay soil were inoculated with two antibiotics marked isolates. Introduced bacteria were always detected in high numbers in the rhizosphere of test plants than in soil apart but they generally represented a small fraction less than 3% of total Azospirillum in the rhizosphere.