Background: Patients with profound intellectual and multiple disabilities (PIMD) cannot clearly express themselves. Therefore, tacit knowledge (TK) is crucial in caring for individuals with PIMD, while it possibly also plays a significant role in medical consultations. Method: A qualitative inductive, thematic analysis was performed of 14 audio-taped consultations with intellectual disability physicians for patients with PIMD to explore how TK is represented and considered between parents and physicians. Results: Parents conveyed their TK by sensing and perceptions of changes of their child's behaviour. Our findings demonstrate that parents of individuals with PIMD primarily shared TK concerning pain, sleeping issues, and epilepsy. Physicians recognised and incorporated parents' TK, highlighting its significance in patient care. Conclusion: This study underscores the important role of TK in consultations for patients with PIMD. Parents' TK help to shape medical-decisions, urging physicians to validate parents' TK while relating this TK to other types of medical knowledge.