Background: Smartphone-mediated mobile health (mHealth) has the potential to assist patients with medication adherence and disease monitoring. This study aimed to describe the awareness and usage of, and attitudes towards, mHealth among smartphone-owning patients in a tertiary hospital in Singapore.Methods: A self-administered cross-sectional survey was systematically offered to patients at the Singapore General Hospital from August to September 2018. Participants were included if they were at least 18 years old, owned a smartphone, and could speak and read simple English. No identifiable data was collected.Responses were summarized using descriptive statistics. Multiple logistic regression analysis was used to identify factors associated with awareness and usage of, and attitudes towards, mHealth.Results: Four-hundred and two eligible responses were received, with most participants reporting having completed tertiary education (63.7%) and having chronic medical conditions (71.1%), with a mean age of about 43 years. On average, participants were aware of 3.7 out of 7 mHealth functions and used 1.9 functions. Most patients were aware that smartphones could be used for general health/fitness tracking, obtaining health information, and appointment management. Most (76.3%) participants were keen to learn to use mHealth in future, and 63.2% agreed that mHealth could help them better manage their health.Conclusions: Although mHealth usage among patients was low, most patients held positive attitudes towards mHealth. For mHealth to fulfill its potential, strategies to improve the awareness and usage among patients need to be explored.