Circular RNAs (circRNAs) may serve as biomarkers for a potentially non-invasive diagnosis of cancer. To understand their diagnostic performance, a systematic meta-analysis of the published literature was conducted to review the diagnostic efficiency of circRNAs in patients with cancer. Eligible studies published up to November 30, 2017, on PubMed and EMBASE, were selected for the meta-analysis. All studies were carefully and independently reviewed by two researchers based on their titles and abstracts, following which full texts were perused for potential eligibility. All statistical analyses were performed by STATA 13.0 statistical software and Meta-DiSc 1.4. A total of 10 eligible studies were included. The pooled diagnostic odds ratio was 7.265. The pooled sensitivity was 0.708 and the pooled specificity was 0.722. The positive likelihood and negative likelihood ratios were 2.483 and 0.372, respectively. The area under the curve was 0.793. circRNA was determined to be a notably effective assistant diagnostic biomarker for cancer.