Officers carried out six warrants at addresses in Monmouth and Caldicot on Wednesday 26 October.
The operation saw officers carry out the warrants in connection with an investigation into the supply of class A drugs.
During the operation, officers arrested six men, aged between 18 and 50 from the Monmouthshire area, on suspicion of being concerned in the supply of Class A and Class B drugs.
The 50-year-old man was later released under investigation, while the others have been released on conditional bail as enquiries continue.
Quantities of class A, cash and mobile phones were also seized.
Ioan Williams, Inspector for Monmouthshire said:
“This warrant demonstrates our continued commitment to protecting our communities from the harmful effects of illegal drugs.
“The supply of such drugs can have a hugely detrimental effect on our communities, and I hope this reassures residents that if they have concerns or know of any suspicious or unusual activity, they can report it.
“If you have concerns about drug dealing in your area, please call us on 101 or 999 in an emergency. Alternatively, Crimestoppers can be contacted anonymously on 0800 555 111.”