We aimed to investigate the prevalence of hyperhomocysteinaemia (total plasma homocysteine (tHcy) ≥ 10 μmol/l) and its major determinants in rural Chinese hypertensive patients. A cross-sectional investigation was carried out in Lianyungang of Jiangsu province, China. This analysis included 13 946 hypertensive adults. The prevalence of hyperhomocysteinaemia was 51·6 % (42·7 % in women and 65·6 % in men). The OR of hyperhomocysteinaemia were 1·52 (95 % CI 1·39, 1·67) and 2·32 (95 % CI 2·07, 2·61) for participants aged 55–65 and 65–75 v. 45–55 years; 1·27 (95 % CI 1·18, 1·37) for participants with a BMI ≥ 25 v. < 25 kg/m2; 1·14 (95 % CI 1·06, 1·23) for participants with v. without antihypertensive treatment; 1·09 (95 % CI 1·00, 1·18) for residents inland v. coastal; 0·89 (95 % CI 0·82, 0·97) and 0·83 (95 % CI 0·74, 0·92) for participants with moderate and high v. low physical activity levels; 1·54 (95 % CI 1·41, 1·68) and 2·47 (95 % CI 2·17, 2·81) for participants with a glomerular filtration rate 60–90 and < 60 v. ≥ 90 ml/min per 1·73 m2; and 1·20 (95 % CI 1·07, 1·35) and 3·81 (95 % CI 3·33, 4·36) for participants with CT and TT v. CC genotype at methylenetetrahydrofolate reductase 677C>T polymorphism, respectively. Furthermore, higher tHcy concentrations were observed in smokers of both sexes (men: geometric mean 12·1 (interquartile range (IQR) 9·2–14·5) v. 11·9 (IQR 9·3–14·0) μmol/l, P= 0·005; women: geometric mean 10·3 (IQR 8·3–13·0) v. 9·6 (IQR 7·8–11·6) μmol/l, P= 0·010), and only in males with hypertension grade 3 (v. grade 1 or controlled blood pressure) (geometric mean 12·1 (IQR 9·2–14·4) v. 11·7 (IQR 9·2–14·0), P= 0·016) and in male non-drinkers (yes v. no) (geometric mean 12·3 (IQR 9·4–14·8) v. 11·7 (IQR 9·1–13·9), P= 0·014). In conclusion, there was a high prevalence of hyperhomocysteinaemia in Chinese hypertensive adults, particularly in the inlanders, who may benefit greatly from tHcy-lowering strategies, such as folic acid supplementation and lifestyle change.