The incident, which occurred on the A73 near Thankerton at around 4.50pm on Wednesday, involved a Peugeot Bipper van, a Ford Focus driven by a 23-year-old man and a Jeep driven by a man aged 70.
Police Scotland have now confirmed van driver Mary Logan, 62, has died from her injuries.
She had been taken to Queen Elizabeth University Hospital in Glasgow following the crash.
A 21-year-old passenger in the van was taken to the University Hospital in Wishaw, where her condition is described as serious.
The driver of the Ford was taken to the same hospital and his condition is described as stable.
A 68-year-old passenger in the Jeep was treated at University Hospital for minor injuries before being released. The driver of that vehicle was not hurt.