Introduction: A consensus is emerging amongst otologist that obliteration of the mastoid cavity that result after canal wall down mastoidectomy is sound option to prevent cavity related problem such as infection, otorrhea, granulation tissue and hearing loss. Aim:To evaluate the surgical outcome of patients undergoing obliteration of mastoid cavity with postauricular soft tissue vascular flaps in canal wall down mastoidectomy for chronic otitis media with cholesteatoma. Material and Methods: The prospective study (conducted between April2017 to April 2018) randomly assigned patients with evidence of CSOM with cholesteatoma to two group (25 in each group, case and control group). After canal wall down mastoidectomy, undergoing obliteration of mastoid cavity with postauricular soft tissue vascular flap in case group and left open cavity in control group. Results: The result was found that healing rate was 100%, 92.30% and 57.14% for small, medium and large cavity respectively in obliterative group (case), as compared to 100%, 63.63% and 40% respectively in the non-obliterative group (control). Conclusion: The present study concluded that mastoid cavity obliteration is better for elimination of cavity problems after canal wall down mastoidectomy. Ethical consideration: The study protocol was reviewed and approved by institution ethical committee.