Reactive oxygen species generation seems to be one of the important factors in osteoporosis pathogenesis. Aim of study: Comparison of reactive oxygen species (ROS) generation by neutrophils of peripheral blood in postmenopausal women with osteoporosis, osteopenia and normal bone mass density (BMD). Material and methods: 76 postmenopausal women were included in the study. Based on spinal densitometry three groups of women were selected: group I with normal BMD (n=22), group II with osteopenia (n=28) and group III with osteoporosis (n=26). Reactive oxygen species generation by neutrophils of peripheral blood was evaluated using chemiluminescence measurement. Results: Areas under curves and maximal energy values of spontaneous chemiluminescence and stimulated neutrophils show no differences between the mentioned groups. Conclusions: ROS generation by neutrophils in blood of postmenopausal women with osteoporosis and osteopenia do not differ from parameters of this phenomenon in patients with normal BMD.