Objective: To  evaluate the  role of endometrial dying with methylene blue during diagnostic hysteroscopy to detect new subtle histopathologies missed by the conven-tional hysteroscopy. 
Methods: One hundred patients were included in the study complaining of perimenopausal bleeding with no diagnosed hysteroscopic endometrial abnormalities  nor  a general bleeding tendency. Endometrial dying was done by instillation of 5 ml of 1% methylene blue into the en-dometrial cavity after diagnostic hysteroscopy.    Accord-ing to the pattern of methylene blue staining, 60 patients showed focal dark staining  with a background of light blue stained endometrium  forming (group I), the remain-ing 40 patients showed  non focal diffuse blue staining forming ( group II ). Group I  was further subdivided into group A , B  according to the age with group A (40-46 years) and group B (>46 years)..  
Results: Chromohysteroscopy  procedure  led to the di-agnosis of 48  more  new endometrial histopathologies missed by  conventional diagnostic hysteroscopy  includ-ing 16 cases of atrophic endometritis, 29 cases of simple endometrial hyperplasia and 3 cases of atypical endome-trial hyperplasia.The overall validity of the chromohys-teroscopy procedure was calculated with a sensitivity of  93.2%, specificity of  87.8%, positive predictive value of 91.6 % and negative predictive value of  90%.  
Conclusions: Chromohysteroscopy appears to improve the efficacy of hysteroscopy in abnormal uterine bleed-ing  and  observation of diffuse light blue staining without dark areas strongly suggests a normal endometrium free of endometritis.