BACKGROUND: Age at menarche is a reproductive trait, which is largely influenced by environmental factors. Each population has a set of lifestyle factors that may shift age at menarche in different direction. Populations of Eastern Slavs, particularly Ukrainians, are underrepresented in studies of reproductive health. The objective of the present research was to determine important non-genetic risk factors, which may contribute to menarcheal onset in Eastern Ukrainians. METHODS: In total 620 females aged 17-25 years participated in the cross-sectional survey. The questionnaire included lifestyle factors previously reported in other populations as those, which might affect age at menarche. The risk factors for early and late age at menarche were determined using logistic regression models. The models were validated by receiver operating curves. RESULTS: Body composition in the prepubertal stage as presented by responders seems to have the strongest association with age at menarche. Those who were shorter and thinner as compared to their peers at age six had significantly more chance to start menstruating later (OR = 1.66, 95% CI [1.01-2.73]) and reduced chance to have menarche before 12 years old (OR = 0.32, 95% CI [0.14-0.73]). Maternal smoking during pregnancy and low protein intake reported during childhood may decrease a probability of late age at menarche. CONCLUSIONS: Although overall body composition at age of six was a main trait, which was associated with menarcheal timing, more information on body measurements (e.g. waist-hip ratio) in prepubertal stage would help to establish a greater degree of accuracy on this matter.