This is the eighth straight quarter for which Bharti Airtel has reported a decline in net profit.
The company had posted a consolidated net profit of Rs 1,303 crore (Rs 13.03 billion) in the third quarter ended December 31, 2010, Bharti Airtel said.
Shares of Bharti Airtel fell by 3.15 per cent to Rs 367 on the BSE in early trade.
Bharti Airtel said the roll-out of its 3G network resulted in a higher amortisation cost of Rs 164 crore (Rs 1.64 billion) for the quarter, while its net interest cost rose to Rs 116 crore (Rs 1.16 billion) during the reporting period, the company said.
The company's total reveunes rose to Rs 18,477 crore (Rs 184.77 billion) in the October-December quarter from Rs 15,772 crore (Rs 157.72 billion) in the year-ago period, registering a growth of 17 per cent.
"I am pleased that investments in branding and networks continue to be our focus in India, as we enhance customer experience for voice quality and cater to the ever increasing demand for data.
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"These investments are resulting in healthy growth of Mobile revenues.
"Customer milestone and are now one of the fastest growing telecom companies in the continent," Bharti Airtel chairman and managing director Sunil Bharti Mittal said.
The company's overall customer base stood at 243 million across 19 countries.
Monthly average revenue per user, a key metric for telecom carriers, from Bharti's Indian operations rose to 187 during the reporting quarter from 183 in the September quarter.
As of December 31, 2011, Bharti Airtel has a net debt of $12.72 billion.
The revneue from African operations rose by 16.1 per cent year-on year to $1.05 billion during the quarter, it said.