An exoskeleton is a mechanism that works as an external skeleton to assist the human body in daily tasks, rehabilitation, and strengthening. A lot of active exoskeletons have been developed in order to provide assistance to the human body while walking or running. However, developing an unpowered exoskeleton can reduce the human efforts while running is something that requires more attention. The goal is to create a lower limb assistive exoskeleton that will allow people to run while spending as little energy as possible and which is affordable and can be worn easily. The design is entirely mechanical (passive), which means it does not rely on any external electrical energy inputs. This article discusses the design and testing of waist supportive passive exoskeleton for human comfort. Exoskeleton was designed by using silicon-chromium spring steel for manufacturing of leaf spring. The leaf spring was with 50 mm width and 1 mm thick. Total weight of the exoskeleton was 1.5 kg. The stiffness of leaf spring was 56.19 Nm/rad. It has been observed that the proposed design is more comfortable to human beings while running. Composite Materials can be used for manufacturing of various parts of the passive exoskeleton to reduce its overall weight and enhance Mechanical Properties. © 2022