Objective: To study differences in risk factors and clinical variables between a group of patients with osteoarthritis and a group with osteoarthrosis of the temporomandibular joint. Material and methods: Thirty-five patients (32 women and 3 men) (mean age 53±18 years), 21 (60%) with a diagnosis of osteoarthrosis (mean age 54.7±20.2 years) and 14 (40%) with a diagnosis of osteoarthritis (mean age 51.7±16.9 years), were studied. The two groups were compared with each other and also with the group of 164 patients with temporomandibular joint pathology from which they were drawn. An evaluation was made of the demographic variables, risk factors (parafunctions, posterior occlusal contacts, sleep disturbances and psychoactive medication), clinical manifestations (pain, joint sounds, limitation of mandibular movements) and panoramic X-ray and magnetic resonance imaging alterations. Results: None of the studied variables showed statistically significant differences between osteoarthritis and osteoarthrosis. Age was significantly older among the patients with osteoarthritis/osteoarthrosis than in the general group of patients with temporomandibular joint pathology (36.9±17.2) (F=20.1; p=0.000). The time from appearance of the symptoms to medical consultation (35.9±41.8 months) was significantly longer in patients with osteoarthritis (F=3.95; p=0.049). The number of posterior occlusal contacts (5.2±3.0), maximum aperture (32.5±6.5 mm), and the frequency of parafunctions (42.9%) were significantly lower in the group of patient with osteoarthritis (F=6.2 p=0.01; F=4.45 p=0.04; χ2 =4.85 p=0.03) than in the group of patients with temporomandibular joint pathology from which they were drawn. Conclusions: No epidemiological or clinical differences were observed between osteoarthritis and osteoarthrosis, though both processes - particularly osteoarthritis - showed differences with respect to the group of patients with temporomandibular joint pathology from which they were drawn.