From March 1 anyone caught using a mobile phone (or internet device) at the wheel faces a £200 fine and six penalty points on their licence.
The new get-tough law doubles the current penalty, and in the most serious cases drivers can also be prosecuted for careless or dangerous driving.
Chief Superintendent Andy Edmonston, head of road policing for Police Scotland, said: “The risks associated with using a phone while behind the wheel have always been very clear.
“Any driver will be distracted by a phone call or text message as it affects the ability to concentrate and anticipate the road ahead, putting the driver and other road users at risk.
“Distraction reduces hazard perception and increases reaction times in a similar way to drink-driving, making drivers much more likely to cause deaths and injuries.”
He added: “Drivers who think they can multi-task are fooling themselves: - research shows 98 per cent are unable to divide their time without it affecting performance.
“Talking on a phone hand-held or hands free, texting, emailing, adjusting sat navs, eating, drinking and smoking are all proven to increase crash risk.
“The law says a driver must at all times be in proper control of their vehicle.
“If at any time they are not they may be guilty of an offence.
“Police Scotland consistently targets these offences on a daily basis to reduce road casualties and will deal with offences detected in an appropriate manner.
“We are using this change in the law to, once again, remind drivers that using a mobile phone while driving has always been unacceptable and even careful drivers can be distracted by a call or text – and a split-second lapse in concentration could result in a serious or fatal collision.”