While the spread of digital technologies and the growth of associated atypical forms of work are attracting increasing attention, little is known about the impact of these new forms of work on psychological well-being. This paper examines the effect of Uber diffusion on the mental health of drivers, taking advantage of the rollout of Uber across UK regions. We match individual-level information on health and sociodemographic characteristics from the UK Household Longitudinal Study (Understanding Society) between 2009 and 2019 with data on the diffusion of Uber across the country. We first show that Uber diffusion is positively associated with mental health, as measured by the General Health Questionnaire, in the population group of self-employed drivers. We argue that this positive correlation captures a selection effect (of comparatively healthier individuals into the category of self-employed drivers after Uber entry) and the omission of unobserved factors, rather than a causal effect. Indeed, we do not observe any improvement in mental health for workers who were already self-employed drivers before Uber entry. In parallel with this, among individuals who remained salaried drivers over time, our results suggest there may be a decline in mental health after Uber's introduction, probably because they feel the competition from Uber drivers.