We performed comparative analysis of 8-hydroxy-2'-deoxyguanosine in women in different climax stages with and without insomnia. The study involved 90 women aged 45 to 60 years divided into perimenopausal (n=30) and postmenopausal (n=60) groups. After questioning using special sleep questionnaires (Insomnia Severity Index, Epworth Sleepiness Scale, Munich Chronotype Questionnaire), the groups were divided into subgroups with insomnia and without it (control). 8-Hydroxy-2'-deoxyguanosine was assayed in blood serum by ELISA. The higher levels of 8-hydroxy-2'-deoxyguanosine in postmenopausal women with insomnia in comparison with the control and perimenopausal patients (p<0.05) attested to oxidative DNA damage in this cohort of patients.