The men were arrested by officers from Police Scotland's Organised Crime and Counter Terrorism Unit, who searched four different properties in the town of Peterhead, alongside colleagues from the local community policing team.
These searches took place in 2021, on Monday, March 22 and Tuesday, March, 23.
All four of the men plead guilty at the High Court in Glasgow today, Friday, February, 4.
They have been named as Justas Brazinskas, 55, Arturas Litkinas, 32, Romualdas Galdikas, 43, and Tadas Jurjonas, 45.
Following the convictions, Detective Inspector Robin Sim, said: “These arrests were part of an intelligence led operation that had been lengthy and complex and we welcome this conviction.“We are committed to disrupting the illegal and harmful supply of drugs in our communities. We will use every tool and tactic at our disposal to remove these illegal substances from our streets.“We hope this sends a clear message to anyone who is involved in the supply of drugs onto the streets of Scotland that if you expect to profit from other people’s misery, expect to be targeted by law enforcement. No-one is untouchable.“If you have any information or concerns about drug misuse or wider criminality in your area, do not hesitate to contact us on 101 or report anonymously via Crimestoppers on 0800 555 111 where we will investigate thoroughly.”