Objective This study compares the use of sickness absence benefits (SABs) due to a common mental disorder (CMD) between precariously employed and non-precariously employed workers with CMDs. Design Register-based cohort study. Participants The study included 78 215 Swedish workers aged 27-61 who experienced CMDs in 2017, indicated by a new treatment with selective serotonin reuptake inhibitors (SSRIs). Excluded were those who emigrated or immigrated, were self-employed, had an annual employment-based income <100 Swedish Krona, had >90 days of unemployment per year, had student status, had SABs due to CMDs during the exposure measurement (2016) and the two previous years, had an SSRI prescription 1 year or less before the start of the SSRI prescription in 2017, had packs of >100 pills of SSRI medication, had a disability pension before 2017, were not entitled to SABs due to CMDs in 2016, and had no information about the exposure. Outcome The first incidence of SABs due to CMDs in 2017. Results The use of SABs due to a CMD was slightly lower among precariously employed workers compared with those in standard employment (adjusted OR [aOR] 0.92, 95% CI 0.81 to 1.05). Particularly, women with three consecutive years in precarious employment had reduced SABs use (aOR 0.48, 95% CI 0.26 to 0.89), while men in precarious employment showed weaker evidence of association. Those in standard employment with high income also showed a lower use of SABs (aOR 0.74, 95% CI 0.67 to 0.81). Low unionisation and both low and high-income levels were associated with lower use of SABs, particularly among women. Conclusions The study indicates that workers with CMDs in precarious employment may use SABs to a lower extent. Accordingly, there is a need for (1) guaranteeing access to SABs for people in precarious employment and/or (2) reducing involuntary forms of presenteeism.