Temporomandibular disorders (TMDs) are a common group of chronic illnesses. There is evidence that health professionals find them difficult to diagnose and manage. A consequence of this difficulty in diagnosis might be that sufferers of TMDs have an experience of illness comparable with other chronic illnesses. To explore the sufferers? experience of TMDs, we conducted a qualitative study with a purposive maximum variation sample of secondary care TMD patients. Semi-structured interviews were conducted with the sample and were recorded and transcribed verbatim. Data collection and analysis continued until data saturation (n = 19). For analysis, we broadly followed the constant comparative method and used frameworks to organize the data. The key finding was that a lack of diagnosis caused uncertainty over the nature of the cause of the sufferer?s complaint. This uncertainty reportedly caused negative impacts on sufferers? daily lives. Clearly, diagnosis of TMDs needs to be encouraged at the first point of contact.