Lipoprotein (a) [Lp(a)] plays a crucial role in the pathogenesis of deep vein thrombosis (DVT). The purpose of this study was to investigate whether Lp(a) serum levels at admission could be a risk factor for DVT in Chinese patients with acute ischemic stroke (AIS). A total of 232 patients with AIS were included in the study. The patients were assessed for DVT using colour Doppler ultrasonography. We performed colour Doppler ultrasonography 15 days after the stroke and whenever clinically requested. The value of Lp(a) to predict the DVT was analyzed using logistic regression analysis after adjusting for the possible confounders. In our study, 44 out of the 232 patients (19.0%) were diagnosed with DVT at 15-day follow-up. Serum Lp(a) levels were higher in AIS with DVT than in those patients without DVT [656 (interquartile range, 521-898) mg/l vs. 253 (interquartile range, 143-440) mg/l; P<0.0001]. Increased risk of DVT associated with Lp(a) levels greater than or equal to 300 mg/l was found in the multivariate analysis [odds ratio 12.14, 95% confidence interval (CI): 3.08-42.09; P<0.0001]. Visible by the receiver operating characteristic, the optimal cutoff value of serum Lp(a) levels for predicting DVT was projected to be 420 mg/l, yielding a sensitivity of 88.5% and a specificity of 75.4%. With an area under the curve (AUC) of 0.89 (95% CI, 0.84-0.94), Lp(a) exhibited greater discrimination in predicting DVT compared with Hs-CRP (AUC, 0.77; 95% CI, 0.69-0.85; P<0.01), HCY (AUC, 0.76; 95% CI, 0.68-0.84; P<0.01), and NIHSS score (AUC, 0.74; 95% CI, 0.66-0.82; P<0.001). Elevated serum Lp(a) levels were independent predictors of DVT in AIS patients in China, revealing the critical role played by Lp(a) in the pathogenesis of DVT.