Background: The current study focuses on IBS, a common functional gastrointestinal disorder that causes many symptoms that significantly affect a patient's daily functioning. The available evidence that analyzed the link between the intestinal microbiota and mental health indicates that they are reciprocally connected, especially in IBS. Information regarding the gut microbiome profile and IBS patients' psychological state is reviewed to analyze this hypothesis. Objective: To examine the relationship between gut microbiome diversity and psychological state, such as anxiety and depression, in patients with IBS. To examine the relationship between gut microbiome diversity and psychological state, such as anxiety and depression, in patients with IBS. Methods: An observational cross-sectional study that aimed to recruit 150 patients with IBS, as confirmed by the Rome IV questionnaire. Samples were taken from participants' feces, and the microbial richness of their gut was studied using the 16S rRNA gene sequencing technique. Anxiety and depression were measured using the Hospital Anxiety and Depression Scale (HADS). All statistical analysis was conducted using the Statistical Package for the Social Sciences –Version 26. Results: The study found a significant reduction in gut microbiome diversity among IBS patients with high anxiety and depression scores. Specifically, a lower abundance of Bifidobacterium and Lactobacillus was associated with higher HADS scores (p < 0.001). Regression analysis revealed that gut microbiome diversity was a significant predictor of anxiety and depression severity (β = -0.42, p < 0.01). Conclusion: The gut microbiome composition is closely linked to mental health outcomes in IBS patients. These findings underscore the importance of considering the gut-brain axis in managing IBS and related mental health disorders.