Our aim is to define the design and procedure of a 3D printed assistive device and to produce a prototype assistive device for an individual with quadriplegia in order to enable him/her to independently conduct daily living activities. For the design and production of the 3D assistive device, we followed six steps. In the first step-determination of problematic activity/client-centered approach-writing activity was determined as the most problematic activity as a result of the interview with a paraplegic patient. Then, 2D drawings of the assistive device were created as the second step. For the third step the 3D scan of the individual's right hand was obtained. 3D scan of the right hand was transferred to CATIA program and the 3D printer is used in the manufacturing process for the fourth step. In the fifth step, we produced a low-cost novel writing assistive device. The writing device was introduced to the disabled individual and training was given regarding its practical use in the final step teaching the use of the device. As 3D printing technology progresses and becomes more reliable, we believe that the production of assistive devices will become much easier and their use will become more prevalent.