Although the automation level is high within the automotive industry, there is still a high number of manual labour tasks such as in assembly areas. Taking ergonomics programs into account is essential to improve the workstation designs and conditions, which should result in increases in worker output and reductions of discomfort. Work-related musculoskeletal disorders continue to be one of the main problems in the industry today. Exoskeletons are a new technology becoming increasingly important due to its potential reducing loads, they suppose a possible promising solution to advantage in manufacturing environments. The purpose of this study is to evaluate and compare how the use of three different models of exoskeletons affects the range of motion of workers at overhead assembly operations. EksoVest from EksoBionics, Paexo from Ottobock and MATE from Comau have been the passive upper body exoskeletons involved in the present project. To develop the comparison analysis an experiment was designed in which seventeen subjects participated including factory operators and students. The experiment consists of performing three different tasks (drilling operation and stretching) four times, one with each of the exoskeleton models and another without them. Observations, interviews and video and motion capture (Xsens equipment) recordings have been the elements involved in collecting the data. The results have shown that all the subjects agree that exoskeletons help in this specific overhead task, on the contrary, for tasks requiring a larger range of motion the performance decreases. Paexo was the preferred model followed by EksoVest and MATE respectively. However, none of the models got a complete positive valuation. In addition, statistical analysis of the motion capture recorded data have described a trend of keeping the arms raised when using the exoskeletons during the tasks than performing it without them. Positive and negative aspect, activation zone and uses of each of the exoskeleton models are also discussed. To conclude, the results of this thesis highlight the need for design improvements in order to allow a full range of movement to workers and increase user performance in a broader number of applications or tasks as well as to assure a more suitable implementation.