Previous work suggests a four-factor structure of the Modern Health Worries Scale. This study is the first to investigate its dimensionality and factorial invariance across age and sex in a representative population sample (N = 2524) using confirmatory factor analysis. The proposed four-factor model failed to achieve good model fit. Model fit was optimized by allowing correlating error terms resulting in acceptable model fit. Multi-group analysis revealed invariance across age and sex. Our study proved the proposed four-factor structure across age and sex. Consequently, the Modern Health Worries Scale can be applied in general population surveys using subscale scores.