Jute fibers have been studied for their numerous properties and, recently, much attention has been paid to the possibility of using them as reinforcing material in cement based matrices for structural engineering applications. In the context of structural reinforcement methods, the use of composite materials reinforced with synthetic fibers is now quite common, due to their light weight, versatility and adaptability. However, in recent years, the scientific community has been interested on the use of natural composite materials, with the goal of finding innovative solutions with renewable, recyclable, sustainable and biodegradable products for the construction industry. This research investigates the use of jute fibers to assess their suitability as reinforcing materials in cementitious composites for historic/ existing masonry structures retrofitting. As a matter of fact, these applications have to consider the possible low durability of jute, like all other cellulose-based fibers, especially into alkaline environments. This work reports the ongoing experimental investigation to set the mechanical performance of jute fibers. The experimental program considers jute yarns in their natural condition and evaluates how the alkaline matrices would affect the fiber mechanical properties. The paper summa rizes the first results obtained from durability tests on jute yarns as a first step towards the assessment of the long-term performance of Natural Fiber Reinforced Cementitious Composites