The PSU in a filing to BSE said that N K Yadav has "taken over charge of CMD, MTNL," with effect from June 8.
The filing also said that P K Purwar has "relinquished the charge of CMD of MTNL".
MTNL Director Finance Purwar was given additional charge of the post after company's CMD A K Garg retired on May 30, 2014.
Also, Purwar had been selected for the post of MTNL CMD by Public Enterprises Selection Board (PESB) in November 2013.
MTNL has posted a standalone net loss of Rs 595.11 crore in the fourth quarter ended March 31, 2015, due to sharp rise in expenditure and Rs 2,893.39 crore net loss for full year 2014-15.
Shares of MTNL closed at Rs 14.9 a unit, down by 1.32 per cent compared to previous close at BSE today.