The total GSM mobile subscriber base stood at 65.71 crore in December.
The subscriber base witnessed growth after two months of decline in November and December, 2012.
Idea Cellular led the growth by adding 24.5 lakh customers over its subscriber base in December, taking its total subscriber base to 11.64 crore. The company had lost 1.97 lakh customers in December.
Bharti Airtel added 22.86 lakh new subscribers in January and taking its total subscriber base to 18.41 crore.
Vodafone's subscriber base increased to 14.77 crore with an addition of over 2 lakh customers.
However, subscriber base of Videocon dipped by around 13 lakh to 22.57 lakh in January from 36.4 lakh in December, a fall of 38 percent month-on-month.
Aircel and Uninor lost 17.75 lakh and 14 lakh customers, respectively across the country in January. Uninor had 26,550 customers in Mumbai where it closed operations last week.
The data of total GSM user base released by Cellular Operators Association of India included BSNL subscriber base of October, Loop's of September and MTNL's as in December 2012.
COAI data also does not include GSM subscriber base of Reliance Communications and Tata Teleservices.