Objective: Limited joint mobility (LJM), the earliest clinically apparent long-term complication of type 1 diabetes mellitus, is a risk indicator for microvascular complications, and its appearance is primarily affected by long-term metabolic control. We hypothesized that the prevalence of LJM had decreased during the past 20 years. Study design: We examined 312 subjects with type 1 diabetes mellitus, aged 7 to 18 years, using the same examination method and criteria as in studies of 515 subjects in this age group carried out between 1976 and 1978 for whom primary data were available, including age, duration of diabetes, and LJM stage. Statistical analyses included exact χ² tests, independent sample t tests, and unconditional logistic regression. Results: There was a >4-fold reduction in frequency of LJM between 1976-78 and 1998 (31% vs 7%, P < .001), with a decrease in the proportion having moderate or severe LJM (35% vs 9%, P = .025). Conclusions: These findings confirm the hypothesis that the prevalence of LJM has decreased, most likely the result of improved blood glucose control during the past 2 decades. (J Pediatr 2001;138:33-7)