The flexibility of the labour market is considered as an instrument for increasing economic growth.Therefore has the use of flexible employment, also called atypical employment, increased. The atypical employment is characterized by insecurity in comparison with a traditional permanent full- time employment. One of the most common atypical employments is the manning employment, which is insecure whether it is permanent or not. The insecurity in the industry is based on insecure income, unpredictable working hours and poor psychosocial work environment. In order to encourage a continued increase of flexibility in the labour market while the need for security for staffing employees would be satisfied was Directive 2008:104 adopted. A certain amount of security has been achieved. Despite this, remains high mental illness among the staffing employees. Mental illness is based on job insecurity, where, for example unpredictable working hours and high expectations are contributing factors. Young people and immigrants are those groups that in the staffing industry are significantly overrepresented, and young people as a group are also overrepresented both in the general labour market and the industry with temporary employment. Young people are also the group in society who suffers from very high mental illness. The purpose of this essay is to, based on legal regulations and other relevant literature, examine how the staffing industry function and it’s need for flexibility relate to the workers need of security, and potential consequences of flexibility for workers and labour market. I also aim to investigate how already vulnerable groups in society and labor market may be affected by flexibility emergence.