Razdan, who is working as member in the Commission, will be administered the oath as UPSC chief on Saturday, the day incumbent Prof D P Agrawal's tenure ends.
Her new charge comes at a time when the Commission is facing controversy over demand in change of the pattern of civil services examination by students.
She had joined as UPSC member on April 19, 2010.
64-year-old Razdan, a former IAS officer of Haryana cadre, had retired as Secretary, Department of Administrative Reforms & Public Grievances.
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Her assignments at the Centre included Joint Secretary in the Ministry of Food and Additional Secretary in the Ministry of Personnel, Public Grievances & Pensions.
In her home cadre, her assignments included Secretary, Cooperation and Public Health, Principal Secretary, Housing and Chairman, Haryana Housing Board. She has authored a number of publications.
The UPSC is headed by a chairman and 10 members.
Former DoPT Secretary Alka Sirohi, David R Syiemlieh (academician), Manbir Singh (Retd IFS officer), former CBI Director Amar Pratap Singh, Former Navy Vice Chief D K Dewan, Ex-Railway Board Chairman Vinay Mittal, P Kelimsungla and Prof Hem Chandra Gupta (educationists), and former IAS officer Chhatar Singh are the members of the Commission.