Objective To assess the association between incident Parkinson's disease (PD) and subsequent incident epileptic seizures. Methods We conducted a retrospective cohort study with a nested case-control analysis using data from the UK Clinical Practice Research Datalink. We identified patients aged ≥40 years with an incident diagnosis of PD between 1995 and 2016 and a matched comparison group of PD-free individuals. We calculated crude incidence rates (IRs) with 95% confidence intervals (CIs) of epileptic seizures in PD patients and the PD-free comparison group, and corresponding crude incidence rate ratios (IRRs). In the nested case-control analysis, we calculated adjusted odds ratios (adj. ORs) of incident PD among cases with incident epileptic seizures and seizure-free controls overall and stratified by various, seizure-provoking comorbidities. Results Among 23,086 incident PD patients and 92,343 PD-free individuals, we identified 898 patients with incident epileptic seizures. The crude IR of epileptic seizures in PD patients was 266.7/100,000 person years (95% CI 235.6-297.7), and in PD-free individuals 112.4/100,000 person years (95% CI 103.5-121.3) [IRR: 2.37, 95% CI 2.06-2.37]. The adj. OR of epileptic seizures was 1.68 [95% CI 1.43-1.98]) in PD patients compared with PD-free individuals. PD patients with comorbid brain disorders (adj. OR 12.36 [95% CI 8.74-17.48]) or with >1 seizure-provoking comorbidity (adj. OR 13.24 [95% CI 10.15-17.25]) were at the highest risk of epileptic seizures compared with PD-free individuals with no seizure-provoking comorbidities. Interpretation This study suggests that incident PD is associated with an increased risk of incident epileptic seizures. This article is protected by copyright. All rights reserved.