Abstract Background At present, a large number of studies have found that long non-coding RNAs (lncRNAs) can be used as biomarkers for diagnosis and monitoring prognosis of hepatocellular carcinoma (HCC). The expression of lncRNA cancer susceptibility candidate 7 (CASC7) in HCC has rarely been studied. The purpose of this study was to explore the expression of CASC7 and its correlation with clinical features, and to further analyze its diagnostic value in HCC. Methods Serum samples were collected from 80 patients with HCC, 80 patients with chronic hepatitis B (CHB), and 80 healthy people. The expression level of serum CASC7 was detected by droplet digital PCR. Appropriate parametric and nonparametric tests were used for data analysis. Results The results showed that the expression of CASC7 in serum of patients with HCC was significantly higher than that of patients with CHB (median: 8.8 versus 2.2 copies/µl, p