Aim: The aim of this study was to investigate possible impact of the Covid-19 pandemic on general health, mental well-being, and experiences of control compared to pre-pandemic populations. Our hypotheses were that we would observe a significant lower level of psychological wellbeing and general health in the 2020 sample compared to the prepandemic samples, and that we would observe younger age groups to be the most effected. Method: Two representative Danish populations (2016, n=1656) and (2017, n=3366) were compared to a representative Danish population (n=1538) sampled during the first lockdown in May 2020. Two-tailed tests of proportions were used to investigate possible differences between samples in proportions reporting poorer mental well-being measured by WHO-5, general health, and internal locus of control. Results: Younger men (aged 18 24) and younger women (aged 18 – 44) as well as elderly women (aged 65-74) reported lower mental well-being during the early phase of the pandemic compared to the population from 2016. Both women and men in 2020 to report significantly lower levels of internal locus of control compared to the 2017 sample. This was especially true for younger men and women. There were no statistically significant differences in general health between populations. Discussion: This study partly supports the hypothesis that the the Covid-19 pandemic affected mental well-being negatively among younger persons. However, longitudinal studies are needed to investigate possible longterm effects of the pandemic on mental health and well-being. Further, qualitative studies are needed to investigate in-depth the consequenses of Covid-19.