We aimed to investigate the prevalence and distribution of abnormal glucose regulation, including prediabetes and newly diagnosed diabetes, according to different criteria in ischaemic stroke patients without a history of diabetes. Data were derived from a representative cohort across China. Prediabetes was defined as fasting plasma glucose (FPG) 5.6-6.9 mmol/L or 2-hour oral glucose tolerance test (OGTT) 7.8-11.0 mmol/L or haemoglobin A1c (HbA1c) 5.7-6.4%. Newly diagnosed diabetes was defined as FPG ≥ 7.0 mmol/L, 2 h OGTT ≥ 11.1 mmol/L or HbA1c ≥ 6.5%. Among 1251 ischaemic stroke patients, 471 (37.5%) were detected as prediabetes and 539 (43.1%) were detected as newly diagnosed diabetes. Prediabetes was present in 118 (9.4%), 290 (23.2%) and 314 (25.1%) stroke patients, and newly diagnosed diabetes was present in 138 (11.0%), 370 (29.6%), and 365 (29.2%) stroke patients, based on FPG, 2 h OGTT, and HbA1c criteria, respectively. Dependency on FPG alone would have missed 74.9% of patients in the prediabetes range and 74.4% of patients in the diabetes range. Our study demonstrated a high prevalence of prediabetes and diabetes in ischaemic stroke patients without a history of diabetes. OGTT and HbA1c helped detect the majority of prediabetes and newly diagnosed diabetes in ischaemic stroke patients.