Background: Human obesity is associated with a proinflammatory state and an elevated level of mediators, such as C-reactive protein (CRP). Objectives: To establish CRP levels as baseline preoperative values and then at 6 months after bariatric surgery, as well as to determine the changes in weight, body mass index (BMI), leukocytes, and glycemia. Materials and methods: An observational, analytical, retrospective, longitudinal, and open study was conducted. Serum CRP values were measured in 36 adults presenting with morbid obesity, and their baseline relation to weight, BMI, leukocytes, and glycemia was determined; the relation to the same parameters was established again, 6 months after bariatric surgery. Results: The mean and standard deviation of preoperative and postoperative CRP (mg/L) was 1.15 ± 0.86 and 0.34 ± 0.28, respectively with p < 0.0001; weight (kg) 112.10 ± 22.91 and 84.82 ± 17.11, p = 0.0443; BMI (kg/m2) 42.48 ± 5.97 and 32.2 ± 4.79, p = 0.0988; glucose (mg/dL) 100.58 ± 17.82 and 87.11 ± 8.49, p < 0.0001, and leukocytes (× 103/mm3) 8.62 ± 1.69 and 6.99 ± 1.56, p = 0.3192. Baseline CRP only correlated with weight and BMI (p = 0.047 and p = 0.027 respectively) and there was no correlation between postoperative CRP and the evaluated parameters. Conclusions: Preoperative CRP had a significant lineal relation to weight and body mass index. Patients who underwent bariatric surgery had a significant decrease in CRP, weight, and fasting glucose at 6 months after surgery.