Alcohol use in both men and women [from 1.12 to 1.14]. weekend work and non-fixed working hours were associated with increased tobacco and alcohol use in both men and women [from 1.15 to 1.54 and 1.12 to 1.14, respectively]. dose-dependent relationships were found regarding the association between working at night and tobacco use in women as well as regarding non-fixed working hours and tobacco use in both men and women (p for trends <0.001). conclusions: the potential role of atypical working hours on substance use should be considered by public health policy makers and clinicians in information and prevention strategies. key messages: night shifts were associated with increased smoking in women with dose-dependent relationships, cannabis use in men and alcohol use in both. weekend work and non-fixed working hours were asso- ciated with increased alcohol and tobacco use with dose- dependent relationships in men and women