This study aims to determine the effects of Jerusalem artichoke powder (JAP) utilization on the physical quality and nutritional characteristics of sourdough bread. JAP was applied to both sourdough fermentation medium and bread formulation. The increasing rates of JAP had deteriorated effects on the physical properties (specific volume, color, and texture profile) of bread. JAP decreased significantly in vitro starch digestion rate in sourdough bread. The glycemic index value of 20% JAP-containing sourdough bread was detected to be 75.12. Additionally, total dietary fiber content increased from 2.62 to 5.30/100 g, by JAP incorporation. The total phenolic content and antioxidant activity of control were determined as 43.72 mg GA/100 g and 48.78 µmol TE/100 g, respectively. In comparison, these values were 80.60 mg GA/100 g and 130.77 µmol TE/100 g in samples supplemented with 20% JAP. According to the sensory analysis, utilization of JAP, over 10% resulted in quite low points. Practical applications: Inulin is generally used to increase dietary fiber content and decrease the glycemic index of foods. On the other hand, the utilization of foods with inulin-rich JAP not only increases the dietary fiber content but also enriches it with bioactive components and phytochemicals. However, the high addition levels of JAP can deteriorative effects on the sensory features of foods. In this study, due to the specific aroma and sour taste of sourdough bread, JAP was used above the levels stated in the literature without creating a negative effect on the sensory.