Gardaí attached to the Mayo Drugs Divisional Task Force have completed a planned search of a residence in the Westport area, as part of Operation Tara.
Gardaí seized cocaine believed to be worth over €4,000, along with mobile devices, digital scales and other drugs related items.
Four men were arrested in connection with the investigation and detained under Section 4 of the Criminal Justice Act, 1984, for questioning.
All four have been released without charge and await a meeting with the Director of Public Prosecutions.
Gardaí say the investigation is ongoing.