The Communication Workers Union served formal legal notice to the company of its intention to ballot its members.
Ballot papers will go out on September 27, with the result announced on October 16.
If there is a yes vote, the earliest that strike action could take place would be October 23.
It is the first national strike ballot in Royal Mail since 2009 and will affect 115,000 postal workers in Royal Mail and Parcelforce, but not the Post Office, which is a separate company.
The dispute is over pay, pensions and the impact of privatisation on job security, terms and conditions.
Dave Ward, CWU deputy general secretary, said: "The Government's privatisation agenda has destabilised everything. Postal workers are rightly concerned about their future so we want a legally binding agreement on protections for jobs, terms and conditions - regardless of who owns the company.
"We don't want a race to the bottom in the postal industry where companies compete on poverty pay, few employment rights and poor services simply to maximise payouts to wealthy shareholders. Without an agreement, strikes are inevitable."
Royal Mail said it was disappointed the union was pressing ahead with a strike ballot.
A statement said: "Any industrial action, or the possibility of disruption, is damaging to our customers and our business, especially in the run-up to Christmas, our busiest time. It therefore has a direct bearing on our ability to sustain good quality, long-term employment for our people.
"We are committed to reaching an agreement with the CWU to give our customers and employees continued stability."