: Most individuals with irritable bowel syndrome (IBS) are diagnosed by primary health care (PHC) physicians. However, a significant percentage of patients remain undiagnosed or misdiagnosed owing to the lack of knowledge or a systematic strategy regarding the use of ROME IV criteria for the diagnosis of IBS. Thus, in this study, we aimed to assess the knowledge, attitude, and practices among primary health care physicians in Jazan Province, Saudi Arabia, regarding ROME IV criteria for the diagnosis of IBS. : A cross-sectional study was conducted using a pretested self-administered questionnaire that determines participants' sociodemographic data and measures knowledge about ROME IV criteria, targeting PHC physicians in Jazan Province, Saudi Arabia. Data were analyzed using the Statistical Package for Social Sciences (SPSS) v.23. : We included 200 participants, and the majority of participants in our study (approximately 78%) were aware of the ROME IV diagnostic criteria for IBS; this awareness was associated with age, nationality, specialty, and classification. The participants' mean level of knowledge was 4.30 (out of 6). However, knowledge was higher among Saudi and family medicine doctors in this study, as compared to non-Saudi and doctors of other specialties. More than two-thirds of participants who were aware of ROME IV criteria thought that they are sufficient to diagnose IBS; however, only 47.5% of physicians reported using ROME IV frequently in their daily practice. : Most of the participants of this study are aware of ROME IV criteria, and better knowledge was noted among Saudi and family medicine physicians. About 70% thought that ROME IV criteria are effective enough to diagnose IBS, and only about half of the participants use ROME IV criteria in their practice. Therefore, due to its high prevalence in the region, further efforts are required to disseminate basic knowledge and improve attitudes and practices related to ROME IV criteria among PHC physicians of all specialties.