Objective: To report the case of an infertile female patient with cystic fibrosis who was diagnosed with endocervical metaplasia of the endometrium at diagnostic hysteroscopy and successfully treated with an oral estroprogestinic formulation. Design: Case report. Setting: University hospital. Patient(s): A 27- year- old infertile female patient with cystic fibrosis. Intervention(s): Hysteroscopy with multiple random biopsies was performed at the time of the first visit and after a 10- month cycle with an oral estroprogestinic formulation. Main Outcome Measure(s): Hysteroscopic evaluation with target biopsy; histological examinations of endometrial specimens. Result(s): Our patient benefited from a 10- month cycle with an oral estroprogestinic formulation. At the control visit we noticed a significant improvement in the hysteroscopic appearance of her endometrium, and the histological examination confirmed the complete reversion of the metaplastic alterations previously observed. Conclusion(s): The present report suggests a novel histological alteration possibly involved in affecting fertility in women with cystic fibrosis. In addition, the positive response to the estroprogestinic treatment observed in our patient poses new questions regarding the relationship between ovarian hormones and cystic fibrosis transmembrane conductance regulator protein regulation, offering interesting perspectives for a hormonal therapy in the treatment of subfertility in women with cystic fibrosis. Objective: To report the case of an infertile female patient with cystic fibrosis who was diagnosed with endocervical metaplasia of the endometrium at diagnostic hysteroscopy and successfully treated with an oral estroprogestinic formulation. Design: Case report. Setting: University hospital. Patient (s): A 27- year-old infertile female patient with cystic fibrosis. Intervention (s): Hysteroscopy with multiple random biopsies was performed at the time of the first visit and after a 10- month cycle with an oral estroprogestinic formulation. Main Outcome Measure (s ): Hysteroscopic evaluation with target biopsy; histological examinations of endometrial specimens. Result (s): Our patient benefited from a 10- month cycle with an oral estroprogestinic formulation. At the control visit we noticed a significant improvement in the hysteroscopic appearance of her endometrium , and the histological examination confirmed the complete reversion of the metaplastic alterations previously observed. Conclu sion (s): The present report suggests a novel histological alteration possibly involved in affecting fertility in women with cystic fibrosis. In addition, the positive response to the estroprogestinic treatment observed in our patient poses new questions regarding the relationship between ovarian hormones and cystic fibrosis transmembrane conductance regulator protein regulation, Justifiable interesting perspectives for a hormonal therapy in the treatment of subfertility in women with cystic fibrosis.