In a report to the General Assembly, Ban said "United Nations personnel serve in an increasingly dangerous environment and encounter a variety of threats not previously encountered in the history of the Organization."
He urged U.N. member states and host governments to step up efforts to protect the organization's workers, saying, "Diverse security threats against United Nations personnel remain acute."
The report found "significant security incidents' against U.S. personnel increased to 1,793 in 2012 compared to 1,759 the year before.
Twenty-five of 35 deaths were attributed to violence. Another 15 staffers died in safety-related incidents.
Ban noted the steady increase in the abductions of U.N. employees. Thirty-nine workers were kidnapped in 2012, compared to 21 in 2011 and 12 in 2010.
In the first six months of 2013, 15 U.N. personnel were abducted, 12 in Syria alone.
Ban asked member states and the countries in which the employees are stationed to help bring to justice those who threaten the lives or safety of the employees.
"There can be no impunity for anyone who carries out acts of violence against United Nations personnel," Ban said.
He expressed particular concern for local people who work for the United Nations, saying they represent "the great majority" of the organization's staff.