Purpose To assess the relationship between low-grade inflammation, measured as basal high sensitivity (hs)-CRP, and IVF outcome. Methods We recruited a total of 220 women undergoing infertility work up prior to IVF. Patients were selected for a BMI<30 kg/m 2 with an upper age limit of 40 years. Serum hs-CRP levels were measured on day 3 of a spontaneous menstrual cycle preceding ovarian stimulation. A sensitive two-site ELISA was used for analysis. Dose of gonadotrophins required, follicles days 8 and 10, number of oocytes collected, number of oocytes fertilised and pregnancy outcome were recorded. Results Median hs-CRP was 1.08 mg/L (0.43-3.00 mg/L). The hs-CRP was significantly related to BMI (r=0.386, P<.001) but not to age and smoking habit. There were no significant relationships between basal hs-CRP and any of the measured IVF outcomes. Conclusions These findings demonstrate that serum hs-CRP concentration is not a predictive marker of cycle or pregnancy outcome in women undergoing IVF treatment.