Revenue says more than 86,000 people paid tax online this year, up 29% on the previous year.
The returns were filed electronically through its online service ROS by last night's midnight deadline.
More than €2.2 billion in tax was paid online this year, compared with €1.4 billion at the same time last year.
Revenue says a record number of returns - more than 30,000 - were successfully filed on the last day.
Revenue Chairman Frank Daly said the figures showed strong confidence by taxpayers and their agents in the security and efficiency of ROS.