Unifor Local 2458 couldn't reach a tentative deal with Clear Medical Imaging's management, so 130 workers are on strike.
The union is negotiating the membership's first contract since they asked to join the local nine months ago.
"Our members have been left with no choice but to strike to demand fair treatment and respect for the critical role they play in providing imaging services to the Windsor-Essex and Chatham-Kent communities," said Unifor National President Lana Payne.
Payne said the union is ready to return to the bargaining table, "but the employer must address the core issues impacting our members."
Wage parity with regional standards, mandatory overtime, and job security are the sticking points in talks.
Unifor Local 2458 President Ken Durocher criticized management, saying, "This strike is the direct result of the employer's failure to prioritize patient care and fair treatment for workers."
"Health care privatization in Ontario continues to create conditions where profits take precedence over people, and workers are left to face the consequences," said Durocher. "We are prepared to stand firm until a fair deal is reached."
Clear Medical Imaging has 11 locations across Windsor-Essex and Chatham-Kent.