People in Slough, Berkshire, charged on suspicion of burglary, theft or robbery now face compulsory drug testing.
The move is part of a government scheme, which has been designed to cut the number of addicts committing crimes to fund their habits.
Offenders who test positive for Class A drugs will be referred to drug workers while in police custody and later put on a treatment programme.
The Criminal Justice Interventions Programme comes into force on Thursday.
Help and advice
The initiative, which has been running as a pilot in England since last April, has now been expanded into a further 36 areas across the country.
Drug-addicted offenders undergoing treatment will receive help and advice on staying drug-free and ways to start afresh - such as finding work and a home.
Home Office drugs minister Caroline Flint said: "Problem drug users cost the economy between £10bn and £18bn a year.
"Evidence shows that targeting offenders at every point in the criminal justice system reduces re-offending and dependence on drugs.
"We estimate that in 2004/05, drug related crime could be reduced by as many
as 1.5m offences thanks to this programme."