In a statement, the group said some of the bonds - worth a total of €1.25 billion - would mature in 2020, and the rest in 2031.
Felipe Lopez-Galvez, an analyst at Spain's Self Bank, said the debt issuance would "compensate the lack of cash coming in" after the failed listing of Telxius, a subsidiary that manages Telefonica's infrastructure
The company had hoped to raise up to €1.5 billion from the listing, which was scheduled for October 3. It had planned to float up to 40 percent of Telxius.
Shares in the company rose 1.18 percent to €8.80 on Monday on news of the debt issuance.
Telefonica, one of the world's biggest telecoms groups, had a debt pile of €52.57 billion at the end of June.
As such, it is on the hunt for cash and it is also considering a possible listing of its British unit O2, after the European Commission blocked its sale to Hong Kong group Hutchison Whampoa over fears of the impact on prices for consumers.
The group reported a net profit of €1.24 billion in the first half of 2016 - a 42.1-percent drop from the same time last year - due in part to currency fluctuations.