The robbery happened around 8:40 p.m. Wednesday near the intersection of Center and Church streets in the downtown area, according to police.
Police said the woman was walking home from a restaurant with her husband when two male suspects ran at the victim, knocked her to the ground and attempted to grab her purse.
Unable to take the purse from the victim, the two suspects ran from the scene and headed north on Center Street.
The elderly woman suffered a fractured pelvis and other serious injuries and has been undergoing treatment at Dominican Hospital.
Detectives searched for video surveillance from businesses and homes in the area and were able to find footage of the suspects at the Santa Cruz City Hall complex.
Police said the suspects are described as white or Hispanic males in their mid to late teens with dark hair.
Both were wearing shorts, and one had a white T-shirt with a small logo on the left chest and a larger logo on the back. The second suspect is believed to have been wearing a blue and white checkered shirt which he appears to have removed after the attack.
Detectives are working with the victim to provide an artist's rendering of the suspects.
Surveillance video of the suspects can be found on the Santa Cruz Police Department's YouTube channel under "Santa Cruz Police Media" or on the department blog at santacruzpolice.blogspot.com.