The company had posted a profit of Rs 449.2 crore in the same period a year ago.
For Idea, this is the second consecutive consolidated loss in two back-to-back quarters as the company viewed the October-April period as particularly harsh and a 'period of telecom discontinuity'.
For the October-December 2016 quarter, Idea has posted its first-ever consolidated net loss of Rs 383.87 crore compared to a net profit of Rs 659.35 crore in the year-ago period.
The October-April 2017 interval can be best described as Period of Telecom Discontinuity, permanently changing mobility business parameters," Idea Cellular said in a statement.
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Total revenues of the company declined by 13.7 per cent at Rs 8,194.5 crore from Rs 9,500.7 crore it registered a year ago in the corresponding quarter.
Annual income of Idea Cellular declined marginally to Rs 35,882.7 crore at the end of 2016-17 from Rs 36,162.5 crore it reported at the end of the previos fiscal.
In an effort to retain its existing mobile subscribers, Idea said it was forced to reduce on sequential quarterly basis, its voice rate by 12.5 per cent to 25.9 paise per minute compared to 29.6 paise in the previous quarter of 2016-17 as well as it dropped its mobile data rate by 27.6 per cent to 11.5 paise per megabyte compared to 15.9 paisa in the third quarter of 2016-17.
Idea Cellular also blamed tsunami of minutes terminating on Idea network from the new operator, resulting in overall higher ratio of incoming minutes recorded at below cost inteconnection usage charge rates" for fall in blended voice realisation rate.
The impact of free extended promotions was even more pronounced on mobile data business.
Idea witnessed a sequential quarterly decline of 6.4 million mobile data customers on the back of 5.5 million loss in October-December 2017 versus second quarter of FY 2017.
The 'non voice revenue' (including data) contribution to the 'overall service revenue' fell to 24.9 per cent as mobile data revenue contribution declined to 18.3 per cent.
"However, the company remains optimistic of revival of mobile data subscriber addition and data revenue in FY 2018 as wireless broadband prices become more affordable for higher adoption by the Indian masses across all socio-economic & geographic segments," Idea said.