Streptomyces scabies (Thaxter) causes destructive and serious damages to many vegetable field crops, including potato. Fourteen pure isolates were obtained from naturally diseased potato tubers showing symptoms of common scab disease, collected from different localities of Sohag governorate, Egypt. All tested isolates were identified as S. scabies (Stc) according to morphological and biochemical tests. Isolate Stc 10 exhibited the highest activity of polyphenoloxidase enzyme, followed by isolate Stc 11, while isolate Stc 2 produced the lowest activity of this enzyme. Concerning the peroxidase activity, the isolates varied in their production; Stc 11 exhibited the highest activity enzyme, followed by isolate Stc 2, whereas isolate Stc 10 produced the lowest activity of enzyme. In regard with Tyrosine Amonnia Lyase (TAL) activity, isolate Stc 2 exhibited the highest activity, followed by isolate Stc 10, whereas isolate Stc 11 exhibited the lowest activity. Agarose gel electrophoresis of the PCR amplification products revealed a band representing the expected 279 bp DNA fragment in each DNA extracted from the highly pathogenic isolates Stc 10 and 11. The results demonstrated