Aims Physical activity has been proposed to be an effective non-pharmacological method of reducing systemic inflammation and therefore may prove particularly efficacious for women with polycystic ovary syndrome (PCOS) who have been shown to have high levels of inflammation and an increased risk of type 2 diabetes (T2DM) and cardiovascular disease (CVD). Therefore, the aim of the present study was to assess whether modest changes in daily step count could significantly reduce levels of inflammatory markers in women with PCOS. Subjects and Methods Sixty-five women with PCOS were assessed at baseline and again at 6 months. All had been provided with an accelerometer and encouraged to increase activity levels. Multivariate linear regression analyses (adjusted for age, ethnicity, baseline step count, change in BMI and change in accelerometer wear-time) were used to assess changes in daily step count against clinical and research biomarkers of inflammation, CVD and T2DM. Results Mean step count/day at baseline was 6337 (±270). An increase in step count (by 1000 steps) was associated with a 13% reduction in IL6 (β: −0.81 ng/L; 95% CI, −1.37, −0.25, P = 0.005) and a 13% reduction in CRP (β: −0.68 mg/L; 95% CI, −1.30, −0.06, P = 0.033). Additionally, there was a modest decrease in BMI (β: 0.20 kg/m²; 95% CI, −0.38, −0.01, P = 0.038). Clinical markers of T2DM and CVD were not affected by increased step count. Conclusions Modest increases in step count/day can reduce levels of inflammatory markers in women with PCOS, which may reduce the future risk of T2DM and CVD.