Purpose. We analyzed the changes of ocular surface parameters and symptoms in healthy and dry eye women over the menstrual cycle, since incomplete reports appeared in the literature on this issue in healthy women still in the fertile age, and none on dry eye women of the same age. Methods. 29 females in the fertile age and a regular 26-29 days menstrual cycle were included in the study. 14 subjects suffered and 15 not suffered from dry eye symptoms. Symptoms were scored by the validate questionnaire OSDI. Degree of dryness was evaluated with the Schirmer test I, Jones test, BUT, Ferning test, Tear Function Index (TFI) and imprint conjunctival cytology. Degree of inflammation was evaluated with conjunctival brush cytology and dosage of exudated serum albumin in tears. Hormonal cytology procedures were applied to exfoliated cells in tears. Patients were analysed during menstruation, in the follicular and in luteal phases over two consecutive cycles and results were statistically evaluated. Results TFI, tear stability, surface dryness and inflammation are significantly related to the hormonal fluctuations in menstrual cycle, in particular to the estrogen peak occurring during the follicular phase, especially in dry eye patients. Subjective symptoms appeared to increase in the luteal phase, suggesting the presence of a pre-menstrual syndrome. Conclusions The ocular surface is confirmed to be dependent by hormonal variations; clinicians would take into account these cyclic variations during the examinations of subjects still in the fertile age, affected by dryness symptoms. This work was supported in part through a grant from the Fondazione Cassa di Risparmio in Bologna to Prof. Emilio Campos