Job insecurity is the outcome of an array of socioeconomic, demographic and organizational processes which in recent years have undermined guarantees that were previously obtained in the world of work. New forms of employment contract and new career structures are factors that generate uncertainty. The experience of job insecurity impacts widely on the meanings that people attribute to work. The paper examines these effects in terms of expectations with regard to work, construction of a personal and occupational identity, the meaning attributed to the career, the psychological link with organizations. The paper concludes by identifying the main factors that render the experience of flexibility and uncertainty extremely variable from individual to individual.