Background Obesity is associated with chronic low-grade inflammation, which has been linked to increased morbidity. However, inflammation variably and unpredictably improves after bariatric surgery. This study aimed at (1) evaluating the relationship between amplitude of weight loss and variation of inflammatory parameters after bariatric surgery, and (2) identifying, among clinical and biological baseline parameters, predictive factors of variation in inflammatory parameters. Methods In a prospective cohort of patients who underwent bariatric surgery, serum concentrations of interleukin (IL)-6, IL-10, resistin, leptin, adiponectin chemerin, and C-reactive protein (CRP) were measured preoperatively and 1 year after surgery, and routine clinical and biochemical parameters were retrieved. Univariate and multivariate analyses (partial least square method) were performed to assess how parameters were associated with weight loss and to predict improvement of inflammatory parameters. Results Eighty-seven patients were included (mean weight +/- SD 136.3 +/- 3.2 kg, 35 gastric bypasses, 52 sleeve gastrectomies). In parallel with weight loss (39.5 +/- 13.8 kg), pro-inflammatory markers (IL-6, CRP, leptin, resistin) significantly decreased, and anti-inflammatory markers (IL-10, adiponectin) increased. Multivariate analysis revealed a significant association between weight loss and improvement in inflammatory parameters. Among all the clinical and biological preoperative parameters, baseline chemerin level was the only parameter that was significantly associated with global improvement of the inflammatory status after surgery. Conclusion The amplitude of weight loss 1 year after bariatric surgery was strongly correlated with improvement of inflammatory profile, which could be predicted by baseline plasma level of chemerin. This suggests a key role of chemerin in obesity-driven inflammation, and a potential use as a biomarker.