A man in his 20s was arrested following the discovery of 200 cannabis plants with an estimated street value of €80,000.
The plants were discovered yesterday at a house in Ballinamuch, Longford.
The man was detained at Longford Garda Station under the provisions of Section 4 of the Criminal Justice Act, 1984.
He was released today without charge and investigations are ongoing.
The house was sealed off for a technical examination.