Experimental studies have provided evidence that isothiocyanates (ITCs) from cruciferous vegetables may modulate carcinogen metabolism and facilitate carcinogen detoxification and reduce cancer risk. However, no epidemiological studies on liver cancer were reported. This study investigates the association between urinary ITCs levels and liver cancer risk among men and women in Shanghai, China. A nested case-control study of 217 incident cases of liver cancer and 427 matched controls identified from the Shanghai Women's Health Study and Shanghai Men's Health Study was conducted. Conditional logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) summarizing the association between urinary ITCs levels and liver cancer risk. Compared to those with undetectable ITCs, nonsignificantly inverse association was observed among detectable (OR = 0.80; 95% CI = 0.51-1.26), below-median (OR = 0.76; 95% CI = 0.47-1.24), and above-median concentration (OR = 0.86; 95% CI = 0.52-1.41) with liver cancer risk. Similar patterns were observed when urinary ITCs levels were categorized into tertiles or quartiles. Although our study firstly focused on the association between urinary ITCs exposure and liver cancer risk, we did not find significant results. Future multicenter prospective, different population studies are warranted to validate our findings.