Officers raided an address in Main Street, Kirkliston, where they found £21,000 of herbal cannabis.
Their inquiry led them to Barnton, where they seized £10,000 in cash, along with a small amount of cannabis.
The four – aged 39, 33, 44 and 49 – have been charged over drugs offences and will all appear at Edinburgh Sheriff Court tomorrow.
Detective Inspector Neil Spowart said: “We would encourage anyone with information on potential drug dealers to contact police.”