Purpose One anastomosis gastric bypass (OAGB) is a promising bariatric procedure. We performed this study to evaluate the changes in a group of inflammatory cytokines 12 months after OAGB. Methods A single-arm prospective study was conducted on obese patients who underwent OAGB. The serum levels of the following adipocytokines were monitored pre- and 12 months postoperatively: adiponectin, leptin, interleukin 6 (IL-6), interleukin 8 (IL-8) levels, tumor necrosis factor-alpha (TNF-α), serum amyloid A (SAA), high-sensitivity C-reactive protein (hsCRP), and monocyte chemotactic protein 1 (MCP-1). Results A total of 62 patients were included with a mean age of 43.9 ± 6.8 years old. The serum adiponectin increased significantly from 7.64 ± 0.29 to 8.76 ± 0.42 μg/mL 12 months after the operation (p < 0.001). hs-CRP and IL-6 decreased significantly 12 months after the OAGB from 3323.35 ± 643.4 ng/mL and 3.72 ± 7.7 pg/mL to 1376.81 ± 609.4 ng/mL and 3.64 ± 6.9 pg/mL, respectively (p < 0.001). The MCP-1 showed significant increase in its level after OAGB as well (p = 0.014). In contrary, there were no significant changes in serum levels of IL-8 (p = 0.12) and TNF-α (p = 0.84) 12 months after the operation. The correlation analysis showed significant correlations between initial body mass index (BMI) with serum adiponectin, IL-8, and serum SAA. Conclusion OAGB can significantly impact the inflammatory cytokine profile in obese patients with possible subsequent protection from obesity-related comorbidities such as insulin resistance, cardiovascular diseases, and certain cancers. Keywords Bariatric surgery . Inflammatory Adipokines . One anastomosis gastric bypass