Householders will see their electricity bills reduced by 5.4% from midnight.
The reduction will lead to an average yearly saving of €50 for ESB’s 1.9 million residential customers.
There will also be a price drop of 10% for medium sized businesses and almost 6% for small businesses.
The Commission for Energy Regulation (CER) said the reductions reflect lower gas prices.
Household gas prices fell by almost 10.6% on October 1.