Dublin comes four places ahead of London, which ranks 10th in the list.
And according to the figures, Ireland as a whole is 10th in Europe, with a worse record for violent deaths than England and Wales.
In Ireland and Britain, only Glasgow comes ahead of Dublin -- in fifth place. Latvian capital Riga was number one on the list.
The figures show Ireland has a significantly higher murder rate than most European countries, including those with a large organised crime problem, such as Italy, the Netherlands and Spain.
By far the highest homicide levels are in Lithuania, Latvia and Estonia.
The figures are featured in the annual crime trends survey of the UN Office on Drugs and Crime. The statistics cover the years 2005 and 2006.
A total of 78 countries around the world were surveyed for the report, which featured a breakdown of the largest cities in 29 European countries.
Homicide definitions vary across Europe and in Ireland, it includes both murder and manslaughter.
Ranking in the survey is established by the number of homicides per 100,000 of the population.
In 2005, there were 65 homicides in Ireland, with 67 the following year. By comparison, there were 755 murders in England and Wales, 109 in Scotland and 23 in Northern Ireland.
The Republic had 1.59 murders per 100,000 people, while England and Wales had 1.41 and Northern Ireland had 1.33, making it 13th on the list.
Lithuania had a rate of 8.13, while Scotland and Finland both had 2.13.
The world's highest murder rate is in the South American state of El Salvador, where there were 58.07 homicides per 100,000 people in 2006.
The US had a rate of 5.62.
In terms of cities, Dublin's 3.02 rate compares with 2.25 in London, 5.34 in Glasgow, 3.37 in Belfast, and 7.56 in Riga.
European capitals with a much lower murder rate than Dublin included Rome at 0.96, Prague at 1.69, Madrid (1.18) and Berlin (1.47).
Ireland's placing on the league table could rise next year, when the 2007 figures are set against other countries.
Last year, there were 84 homicides in Ireland, including six incidences of manslaughter.
The 2008 figures which have not yet been complied are expected to show a significant drop in the number of homicides.