Bethan Jenkins AM has been banned from driving for 20 months after Cardiff Magistrates found she had been more than twice over the legal drink-drive limit.
The South Wales West AM was stopped by police in Cardiff at 1.30am on October 14 after driving 'erratically'. She had been at a friend's 40th birthday party the evening before.
The court was told that, rather than stay at her friend's address in the Welsh capital, she instead decided to drive back to her parents' home.
Prosecutor Ian Dawes said when officers pulled over Jenkins' car she was wearing pyjama bottoms and a hooded top.
A blood test gave a reading of 194 microgrammes of alcohol in 100 millilitres of blood. The legal limit is 80.
The 30-year-old was suspended from her party, Plaid Cymru, following the incident.
For more on this story
More top news
South Wales Police tweeted in the early hours of Sunday morning that they had been caught on a stretch of the M4 near Port Talbot.
Cloudy and damp for most of us with outbreaks of rain.
More than 200 people attended the service after Bethel Community Church was destroyed by the fire.