Prime Minister Joseph Muscat has left for New York to participate in the United Nations General Assembly and the Climate Change Summit.
The assembly is expected to focus on the situation in Ukraine, Syria, Iraq and Libya and the spread of Ebola.
Dr Muscat is expected to hold a range of bilateral meetings and will also chair a conference on Commonwealth reform, ahead of next year's Commonwealth summit in Malta.
He will also meet the Maltese communities in New York and in San Francisco.
The Department of Information said he is accompanied by Foreign Minister George Vella.