The ESAT-BT Young Scientist of the Year has been won by a 16-year-old student from Dublin's Synge Street Christian Brothers' School.
Ronan Larkin won the competition with his maths project, 'Generalised Continued Fractions'.
The judges said Ronan's project was "a superbly presented development of new techniques for solving difficult equations of mathematics".
Ronan wins a cheque for €3,000, a Waterford Crystal trophy and the opportunity to represent Ireland at the European Union Contest for Young Scientists taking place in Dublin in September 2004.
A project on artificial intelligence entiteld "Emulating Human Response" by Patrick Collison, from Castletroy College in Co Limerick, was awarded the second prize in the individual category.
The group award was presented to Róisín McCloskey and Brendan Hill from Lumen Christy College, Derry, who conducted a study of the dynamics of sandpiles.
Three students from Moyne Community School in Co Longford, Raymond Galligan, Christina Hannify and Angela Mulligan, won the runner-up prize for their project on teen smoking.
The awards were presented by the Minister for Education and Science, Mr Dempsey, at the RDS in Dublin this afternoon. There were over 1,000 participating students and 471 projects.