Cyberchondria is a clinical entity of excessive and repetitive online health-related searches, associated with health anxiety, obsessive-compulsive symptoms and intolerance of uncertainty. Its relationships with depressive and somatic symptoms have not yet received much attention. The purpose of this study was to examine the individual and comparative effects of several psychopathology constructs on the severity of cyberchondria. Through an online platform, participants (N = 749) completed specific self-report measures assessing the severity of cyberchondria, anxiety, intolerance of uncertainty, depressive, somatic, and obsessive-compulsive symptoms. Standard and hierarchical multiple regression analyses were used to assess how well the independent variables influenced the levels of cyberchondria, before and after controlling for age, education, and sex. When measures of all constructs were included in the analysis, all were significant predictors of cyberchondria levels, except for anxiety. Health anxiety made the strongest contribution. When age, education and sex were controlled for, all measures except for anxiety were also significant predictors of cyberchondria severity. Our study confirms that health anxiety, obsessive-compulsive symptoms and intolerance of uncertainty are all associated with cyberchondria severity, with health anxiety making the strongest unique contribution. Depression and somatic symptoms also predicted cyberchondria severity. These findings have important implications for research and clinical practice.