Small and Medium Enterprises (UKM) Lestari Jaya is one of the home industries in Pucuk Village, Tulungagung Regency that produces chips from processed cassava ingredients which are commonly called samiler. These samiler chips are produced using manual methods so that the production process still depends on workers. So far, the work chairs used for military production, especially in the printing process, are not ergonomic and cause fatigue. This work chair is said to be not ergonomic in terms of the form of the backrest that is far from the back of the worker, the size that does not fit the worker’s body shape, the chair material is made of plastic and the resistance of the chair in accepting body loads. Based on data from the Nordic Body Map questionnaire distributed to workers, chairs that are not ergonomic can cause fatigue in workers. Based on the above problems, a study was carried out to redesign an ergonomic work chair with the aim of reducing the risk of fatigue in workers. The anthropometric calculation of percentiles is used to determine chair size. The data is in the form of the 95th percentile for the seat height (45 cm) so that it can be used for people who have long or short legs, the 95th percentile for the width of the seat base (44.02 cm) so that the size of the seat base is wide, the 50th percentile is for the back height ( 56.58 cm) so that it can be used for tall and short people, the 50th percentile is for the length of the seat base (44.93 cm) so that people with large and small popliteal bottoms can use this chair, and the 50th percentile is for the height of the armrests (23, 95 cm) to fit the average human hand size. The advantages of this chair design are that it is stronger, the size of the chair is in accordance with the worker’s body size and the addition of functions, namely that the chair’s height can be raised or lowered according to the worker’s body size