In clinical practice, healthcare professionals increasingly encounter patients from diverse cultural and geographic backgrounds. Despite universal healthcare access, several studies report poorer perceived health among immigrant populations and individuals from French Overseas Departments and Territories. Beyond structural and socioeconomic factors, this study explores whether cognitive mechanisms within medical reasoning contribute to these disparities.To identify cognitive biases influencing the clinical reasoning and management of patients of non-European origin.A qualitative study was conducted between March and September 2024 using semi-structured interviews with eleven physicians practicing in mainland France and the overseas departments. Data were analyzed thematically using a grounded theory approach to model how biases arise during clinical reasoning.Interviews revealed that cognitive biases emerge at several key stages of patient care. Initial interactions were often hindered by linguistic barriers, limiting the collection of clinical information. During data integration, physicians’ emotions, experiences, and structural context intersected with cultural and socioeconomic factors, shaping their interpretations and decisions. Focusing on patients of non-European origin, we identified specific cognitive biases, including difficulties recognizing dermatological signs on darker skin tones, diagnostic overshadowing related to cultural assumptions, and the influence of stereotypes on pain assessment. Despite these challenges, many physicians demonstrated reflexivity and efforts to question their reasoning and the cognitive processes affecting their practice.Methodological rigor was ensured using the COREQ checklist. Nevertheless, snowball sampling may have introduced a selection bias toward motivated respondents. To address potential investigator subjectivity and social desirability bias, the interview guide was iteratively refined. Recall and information biases, inherent to participants’ narratives, were acknowledged as consistent with qualitative research dynamics.Cognitive biases are inherent to medical decision-making and can be reinforced by patients’ ethnic or cultural categorization.  These biases contribute to unequal care by influencing diagnosis and treatment decisions. Raising awareness among healthcare professionals and institutions about these mechanisms, and integrating training on cognitive biases and cultural competence are essential strategies to improve equity in healthcare delivery, particularly for non-European patients.