Introduction: Obsessive-compulsive disorder (OCD) and bipolar disorder (BD) are two psychological disorders that can greatly impair psychological, emotional and communication wellbeing. Aim: The present study sought to compare physical health and thought-action fusion in OCD patients, BD patients and normal (non-clinical) individuals. Method: The present study is a causal-comparative study with a target population consisting of all inpatient and outpatients of Fatemi Hospital and psychiatric clinics in Ardabil between December 2019 to February 2020, and June to July 2020 who were diagnosed with OCD or BD by professionals. Of those, a convince sample of 40 individuals with OCD, 40 with BD and 40 normal individuals was selected for research. The measures used in this study were Rachman and Shafran's Thought-Action Fusion Scale and Abbasi et al.'s Physical Health Questionnaire. Multivariate analysis of variance was performed using SPSS version 25 to analyze data. Results: Results showed statistically significant difference in physical health and its components between OCD, BD and normal patients (p<0.01). A similar significant difference in relation to thought-action fusion was also observed between the OCD, BD and normal groups (p<0.01). That is, normal people have less thought-action fusion than the other two groups. Conclusion: Based on the findings of the present study, we suggest that to specifically target cognitive biases in treating OCD and BD, the role of physical health and thought-action fusion should be taken into account.