Purpose: The aim was to investigate whether the replacement of lost teeth with implantsupported fixed prostheses (IFP) had any influence upon the signs and symptoms of temporomandibular disorders (TMD). Materials and Methods: The subjects comprised 78 consecutive patients referred to a specialist clinic for treatment with IFPs. All were examined with respect to the presence of signs and symptoms of TMD before the start of treatment and after 1 and 3 years. Results: Before treatment began, 21% of the patients were found to have moderate (15%) or severe (5%) clinical signs of dysfunction according to the Helkimo index. These figures decreased numerically but not statistically significantly to 10% and 1%, respectively, at the 3-year follow up. Nearly half of the patients (45%) reported one or more subjective symptoms of TMD at the first examination. The anamnestic index used had decreased statistically significantly at the 3- year follow up, when the 5 variables composing the index had improved, but the improvement was statistically significant only for the variables joint sounds and pain when opening the mouth wide. All patients were satisfied with the treatment received. Conclusion: The results from the present investigation show that treatment with IFPs has a good and lasting effect on the functional status of the masticatory system as well as on subjective symptoms of TMD and chewing ability in the vast majority of patients treated.