This PhD thesis deals with rationalization strategies and occupational health and safety. Tradition-ally, the implementation of rationalization strategies has been expected to lead to bad occupational health and safety standards, e.g. by leading to a faster pace of work. However, recent rationalization strategies, among others Lean, claim to improve working conditions. The aim of this thesis is to identify whether the application of Lean strategies leads to a reduction of the occupational health and safety problem repetitive work. Repetitive work is a problem created by the Taylorisation of work, and therefore it is to be expected that a break with one or more of the Tayloristic principles can lead to a reduction of repetitive work. This thesis points out a number of areas within which Lean breaks with Tayloristic principles, whilst other principles are maintained. These breaks between Lean and Taylorism are also found in the study of the case company. By linking breaks with Taylorism with solutions for the reduction of repetitive work, I point out a number of openings in Lean that may lead to a reduction of repetitive work. By using the concept of openings I present the possibilities offered by Lean for reducing re-petitive work, but also the fact that actors must enter the field to take advantage of these openings. The conclusion is that the concept of Lean presents openings, but also that the implementation of Lean does not in itself lead to a reduction of repetitive work or an improvement of the occupational health and safety. There is nothing in the concept of Lean which assures that repetitive work is re-duced or that the occupational health and safety is improved. The possibilities offered by Lean must be activated by actors within this field to ensure a reduction of repetitive work. Improvements in occupational health and safety, including a reduction of repetitive work, in connection with the im-plementation of Lean do not just happen, but must be actively pursued.