The strain BY-445 which produces new inhihitors of ${alpha}$-amylase was isolated from a soil sample and identified. The aerial hyphae of this strain develope in the from of open spirals. The spore chain of BY-445 strain appears in spiral shape with spiny surface. Melanoid and soulble pigments were not observed. Gelatin was liquefied, and skin milk and starch was also hydrolyzed. The isolate contained LL-diaminopimelic acid in its cell wall hydrolysate. The content of fatty acid 16:iso, 15:0 anteiso and 16:0 was 25:30, 16.19 and 13.16%, respectively. BY-445 strain was closely related to Streptomyces violaceusinger but it was different from this strain in some cultural and physiological characteristics. This strain was, therefore, designated as Streptomyces sp. BY 445.