Background <p>Evidence regarding the risk of incident kidney failure based on developmental disabilities remains scarce. Accordingly, we examined the risk of kidney failure in individuals with intellectual disability (ID) and autism spectrum disorder (ASD).</p> Methods <p>This retrospective cohort study used data from the National Disability Registry of Korea and identified all individuals registered with ID/ASD between 2004 and 2020. In total, 155,729 individuals with ID and 22,385 with ASD and their age- and sex-matched controls (<i>n</i> = 467,187, and 67,155, respectively) were included and followed up until December 2023. Cox proportional hazard analyses were performed to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of kidney failure in individuals with ID/ASD compared with controls.</p> Results <p>A total of 1,058 kidney failure events were identified in the ID cohort (687 ID and 371 controls) and 20 events in the ASD cohort (16 ASD and 4 controls). Individuals with developmental disabilities had a higher kidney failure risk than controls, with adjusted HRs (95% CIs) of 5.50 (4.75–6.36) for ID and 8.62 (2.68–27.74) for ASD. In subgroup analyses, both ID and ASD were associated with an increased risk of kidney failure in most subgroups. Age, sex, income level, and comorbidities showed a significant interaction with ID in relation to kidney failure risk (all <i>p</i> &lt; 0.01), whereas no significant interaction was observed between baseline characteristics and ASD.</p> Conclusions <p>Individuals with ID and ASD had an increased risk of incident kidney failure. Tailored preventive strategies against kidney failure are warranted for this population.</p> Graphical abstract <p></p>