Worldwide, the design of a sewing workstation in many garment industries is often executed with minimal consideration of anthropometrics data. This oversight can lead to hazards and decreased work efficiency due to prolonged sitting in uncomfortable positions. The aim of the study is to identify the relevant anthropometric data necessary for the proper ergonomic redesign of the chair used in the sewing workstation, Rivatex East Africa Limited (REAL) Company. Eleven anthropometric measurements were taken from workers using ISO 7250-1:2017 and analyzed using one-way analysis of variance (ANOVA). The ANOVA t-tests rejected the null hypothesis (P < 0.05) in four dimensions: shoulder height, sitting; buttock popliteal length; buttock knee length; and thigh clearance. This indicates that the means of the different samples are not equal, demonstrating a statistically significant difference among the anthropometric data sets between male and female sewing workers. A comparison of the existing and proposed sewing workstation dimensions against the worker’s anthropometric measurements dimensions, before and after the anthropometric integration. This revealed that the seat height relative to popliteal height, sitting decreased from 63% to 33%, seat depth relative to buttock popliteal length decreased from 81% to 21% and seat width relative to hip breadth, sitting decreased from 79% to 67%. The results of this study demonstrated that an ergonomically redesigned, based on the workers’ anthropometric data, can significantly reduce the mismatch between sewing workstation dimensions and the body dimensions of the workers. Based on the analyzed anthropometric data, a model of the sewing chair was recommended.