The National Organisation for Reform of Marijuana Laws (NORML) is holding a demonstration in Dublin this afternoon calling for the drug to be decriminalised.
The group said it would benefit to the Irish economy if cannabis were legalised and sold through reputable outlets.
The rally started in the Garden of Remembrance in Parnell Square and is making its way towards Leinster House.
Director of NORML Ciarán Maher said: "The issue of cannabis in our society isn’t one that's going to go away. It's the third highest used drug in the country after alcohol and tobacco.
"Criminal gangs are making massive profits off this. For society as a whole it would be far better if it were taken away from the criminals and into the legitimate tax economy."