Increasing evidence demonstrates that by acting as microRNA sponges modulating gene expression at the transcriptional or post-transcriptional level, circular RNAs (circRNAs) participate in the pathogenesis of a variety of diseases and are considered ideal biomarkers of human disease. To examine the expression of circRNA_103516 in inflammatory bowel disease (IBD) and its associations with clinical phenotypes and inflammatory cytokines. Peripheral blood mononuclear cells (PBMCs) were obtained from patients with IBD, healthy controls (HCs), and patient controls (PCs). Expression of circRNA_103516 and hsa-miR-19b-1-5p was assessed by quantitative reverse transcription-polymerase chain reaction. Crohn's disease activity index (CDAI), Mayo score, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR) were measured. To assess the inflammatory cytokines tumour necrosis factor α (TNF-α), interferon-γ (IFN-γ), and interleukin-10 (IL-10), blood samples were analysed by flow cytometry. Ninety Crohn's disease (CD) and 90 ulcerative colitis (UC) patients, 80 HCs, and 35 PCs were included in the study. CircRNA_103516 was upregulated in CD and UC patients compared with HCs and PCs (P < 0.05). The area under the curve of circRNA_103516 for diagnosing CD and UC was 0.790 and 0.687, respectively. In addition, circRNA_103516 levels were increased in active CD and UC compared with remittent groups (P = 0.027, P = 0.045). Furthermore, in CD, circRNA_103516 correlated positively with CDAI (P < 0.001), CRP (P < 0.001), ESR (P < 0.001), TNF-α (P < 0.001), and IFN-γ (P < 0.001) and negatively correlated with IL-10 (P = 0.006). In UC patients, circRNA_103516 correlated with Mayo score (P < 0.001), CRP (P < 0.001), ESR (P < 0.001), TNF-α (P < 0.001), IFN-γ (P =0.011), and IL-10 (P = 0.002). Additionally, circRNA_103516 correlated positively with stricturing (P = 0.018) and penetrating (P = 0.031) behaviour. Moreover, hsa-miR-19b-1-5p correlated negatively with circRNA_103516 in CD. CircRNA_103516 levels in PBMCs can be considered an ideal candidate biomarker for diagnosing IBD. Dysregulation of circRNA_103516 may participate in the molecular mechanism of IBD through hsa-miR-19b-1-5p sponging. ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.