Aims: To investigate the association between measures of peripheral neuropathy (PN) and impaired left ventricular diastolic function, and the prognosis in patients with type 1 diabetes (T1DM) and no known cardiovascular disease (CVD), and to test the incremental prognostic value of including measures of PN and diastolic function to the established Steno T1 Risk Engine. Methods: Echocardiography and quantitative biothesiometry was performed to evaluate diastolic function and PN. The participants were categorized according to severity of diastolic function and PN. The study endpoint was combined cardiovascular (CV) events and all-cause death. Associations were analysed using multivariable regression models. The prognostic capability was assessed with Harrell's C-statistics and tested against the Steno T1 Risk Engine. Results: A total of 946 individuals (51.5% men) were included. The mean (SD) follow-up was 6 (1.3) years. The total number of CV events and all-cause death were 100. In the multi-adjusted analysis, both PN and impaired diastolic function were associated with increased risk of CV events and all-cause death: severe PN versus no PN: hazard ratio (HR) 2.23 (95% confidence interval [CI] 1.06–4.68; P = 0.035); severe diastolic impairment versus normal function: HR 2.27 (95% CI 1.16–4.44; P = 0.016). Measures of diastolic function improved prognostic capability when added to the Steno T1 Risk Engine: C-statistic 0.797 (95% CI 0.793–0.817) versus 0.785 (95% CI 0.744–0.825; P = 0.006). Conclusion: Peripheral neuropathy and impaired diastolic function are associated with an increased risk of CV events and all-cause death in patients with T1DM. Measures of diastolic function improved prediction of prognosis by the Steno T1 Risk Engine.