Introduction: Limited joint mobility syndrome (LJMS) appears exclusively in both type 1 and type 2 diabetic patients. It is characterized by a limited range of digital motion, with involvement of small joints of the hands. It initially affects the proximal interphalangeal joints, followed by wrists, elbows, shoulders, knees, and axial skeleton. The diagnosis can be made by the simple «prayer sign» test. The objective was to study the prevalence of diabetic patients with LJMS, and to evaluate the association between LJMS and metabolic control, and the risk of accidental falls. Patients and methods: A cross-sectional study was conducted in the San Fernando II Health Centre, Madrid (suburbs). The sample consisted of 184 patients with a diagnosis of diabetes of over 5 years from November to March, 2013. The prayer sign was used to define which patients had LJMS. Fall risk was determined using the Timed Up & Go test. Results: A total of 99 patients (53.8%) (95% CI 46.6 to 61) had a positive prayer sign. No statistically significant relationship was found with HbA1c, but there was an association with the Timed Up & Go test (P<.001) (95% CI 1.173 to 1.611). The patients with LJMS had a moderate risk of falls compared with those without LJMS, which was of low risk. Conclusions: The prevalence of LJMS is high. This is the first study that shows a relationship between LJMS and the risk of falls in diabetic patients. © 2013 Sociedad Española de Médicos de Atención Primaria (SEMERGEN).