Processing lamb meat into fermented sausages can reduce the risk of spoilage and extend shelf life. Fermented sausages are commonly made using lactic acid bacteria (LAB), resulting in a product that is acidic and less firm. Therefore, it is necessary to add jack bean flour as a binding agent. This study aims to analyze physicochemical, microbiological and organoleptic characteristics of premium IPB lamb fermented sausages with varying proportions of jack bean flour (0% and 30%). The analyses included pH, water activity (aw), total acid, water, ash, fat, crude protein, carbohydrate, total LAB, E. coli, S. aureus, texture profile analysis (TPA), and sensory evaluation. The incorporation of jack bean flour into lamb meat fermented sausages can elevate the pH, springiness, chewiness, crude protein, and carbohydrate content of the fermented sausages. Furthermore, the addition of jack bean flour may reduce the total acid, aw, gumminess, water content, and bacteria (E. coli and S. aureus). The sensory aspects such as color in fermented sausage with addition of jack bean flour were preferred by the panelists. The addition of jack bean flour increased the total unsaturated fatty acids and essential amino acids in fermented sausages. The incorporation of jack bean flour aligns with the Indonesian National Standards for Meat Sausages 3820–2015 concerning moisture, fat, and protein content. This study suggests that incorporating lamb fermented sausage with 30% jack bean flour could result in significant benefits, including increased nutrition, enhanced sensory quality, improved texture, and extended storage life for fresh lamb products.