In recent years, there has been significant development in the manufacturing of advanced functional fibers. By thermally drawing multimaterials such as polymers, metals, and semiconductors into a single microfiber, we are able to create flexible fiber devices with unprecedented properties and functionalities. Here I present these fiber devices for neural interfacing and distributed sensing applications. Current neural interface devices are mostly based on hard materials such as metal or silicon. The dramatic difference in the elastic moduli between soft tissue and the rigid probe can cause long-term tissue damage and device failure. Furthermore, it is a challenge to incorporate multiple functions into electrical recording probes in order to establish two-way communication with neural circuits in vivo. With the multifunctional fiber based platform, we enable simultaneous electrical, optical and chemical communication with neural circuits in deep brain with minimal tissue damage. These devices could facilitate both fundamental understanding of the functional neural networks as well as clinical applications in treating brain related diseases. Moreover, flexible sensors that can map the pressure and temperature distribution is of great importance to various applications. Here we demonstrate distributed pressure and temperature sensing fibers using frequency domain reflectometry. These fibers can also be woven into a fabric for pressure mapping applications in touch pads, car seats, wearables, etc.