Armed gardaí raided a house before arresting the pair, who are understood to be gangland figures
Two men have been arrested and €50,000 worth of heroin seized in Limerick last night.
Gardaí say the arrests were part of an investigation into organised crime in the city.
The men aged 40 and 43 were detained when armed gardaí raided a house in St Mary's Park.
It is understood both are well known gangland figures.
They are being detained at Henry Street and Mayorstone garda stations and can be questioned for up to a week.