Thirty two local Streptomyces isolates were used in this study to determine their ability to grow in different NaCl concentrations. About 3.125% of these isolates were tolerant to 3% NaCl and 3.125% were tolerant to 12% NaCl. While 93.75% were tolerant to 9% NaCl. The growth characteristics such as growth of aerial and substrate mycelia, colour of aerial and substrate inycelia and pigment production, varied when grown in presence of salt. Four local Streptomyces isolates (LMS-25-9, SH-10, EM and Zj) were chosen for fiirthermicrobiological and genetical studies. These isolates are characterized by their patterns of antibiotics sensitivity and antimicrobial activities. The antimicrobial activities of these isolates were effected when grown in presence of (1.5,3)% NaCl in liquid and solid media. Chemical and physical methods were used for detection the antibiotic produced by the selected isolates. These results suggested that the antibiotics produced belong to tetracyclincs group. These isolates contain only one plasmid of the same size. The plasmid was extracted and detected by using the rapid alkaline lysis method (Kieser, 1984). Curing experiment of plasmid by using acridine orange dye did not eliminate the salt tolerance phcnotype of cured colonies. The optimal conditions for protoplast formation and regeneration of two isolates (Z1 and EM) were carried out according to Al-Azawi (1996). The results showed that the recombination frequency was 18.5% and suggested that salt tolerance is controlled by chromosome. An attempt was made to study the protein patterns of Streptomyces mycelia in absence and presence of NaCl. The result suggested that NaCl induced production of some proteins.