"The draft resolution is not adopted as it failed to receive the necessary amount of votes," UN Security Council President Roman Oyarzun Marchesi said after the vote.
The draft resolution sought to establish an arms embargo on the youngest UN member-state as well as freeze the assets of three government and opposition representatives and introduce a travel ban against them.
The United States prepared the draft resolution in November, but the measure was put up for a vote on Friday.
The South Sudan armed ethnic conflict erupted in December 2013, a year-and-a-half after the nation gained independence from Sudan, when President Kiir blamed First Vice President Riek Machar of preparing a military coup. The conflict forced more than a million people to flee their homes.