The woman, believed to be in her thirties, was involved in a collision with a white Vauxhall Vivaro van near Oxon Priory, Shelton Corner on the Welshpool Road at around 8.30am.
She sustained multiple injuries and was taken to the Royal Shrewsbury Hospital.
A West Mercia Police spokesperson said: “We are appealing for anyone who saw this incident to contact Shrewsbury police station by calling 101.
“It happened near the traffic lights and resulted in the cyclist receiving serious injuries. We are continuing to investigate the circumstances and would welcome any information which will help establish what happened.”
The road remained closed until about 10.45am while the emergency services worked at the scene.