Studies are lacking on the employment determinants of job insecurity, that may be helpful to determine highly exposed groups and to assess the feasibility of constructing job-exposure matrices (JEMs) for this occupational exposure. The objectives were to explore the employment determinants of job insecurity in a nationally representative sample of the French working population. The study was based on the cross-sectional data of the 2013 national French working conditions survey including a sample of 28,293 employees, 12,283 men and 16,010 women. Job insecurity was assessed using one single item related to the fear of job loss in the next 12 months. Gender, age, and educational level were studied as well as the following employment variables: temporary/permanent work contract, full/part time work, job seniority, occupation, economic activity of the company, public/private sector, and company size. The associations with job insecurity were studied using bivariate and multivariate analyses. One quarter of the study sample was exposed to job insecurity, without any difference between genders. Lower age and lower educational levels were associated with job insecurity. Employees who had a temporary work contract, lower job seniority, who were working in low-skilled occupational groups, in manufacturing (for both genders) and construction (among men), and in the private sector had a higher prevalence of exposure to job insecurity. The two major employment variables associated with job insecurity were temporary work contract (prevalence ratios>2) and private sector (prevalence ratios>1.4) for the whole sample and for both men and women. Our findings suggested that intervention/prevention measures could be oriented towards specific highly exposed groups of the working population, especially those exposed to temporary work contract and/or working in the private sector. Our study also underlined that constructing JEMs for job insecurity may be possible and could be a useful tool for large-scale occupational health studies.