Objectives:
The aim of this cross-sectional study was to assess the relationship between Body Mass Index (BMI) and cyberchondria in a sample of men and women. The study also examined the significance of Big Five personality traits as mediators of this relationship.

Methods:
Participants were 329 women and men aged 18 to 65 recruited online. We estimated BMI based on data provided by the participants about their height and current weight. The Ten-Item Personality Inventory was used to assess the Big Five personality traits. Cyberchondria was diagnosed using Cyberchondria Severity Scale (CSS).

Results:
BMI correlated positively with emotional stability (opposite of neuroticism) and extraversion but negatively with cyberchondria. Emotional stability and extraversion correlated negatively with cyberchondria. Only BMI and emotional stability were good predictors of cyberchondria. Women scored lower on BMI and emotional stability scale but higher on the cyberchondria scale than men. The mediation analysis revealed a direct and indirect effects of BMI on cyberchondria through emotional stability as a mediator between BMI and cyberchondria.

Conclusions:
This study highlights the possible importance of the BMI for cyberchondria depending on individuals’ emotional stability. These results may be useful for professionals dealing with a therapy for overweight/obese people as well as for problematic Internet users.