The news comes after four cases — two children and two adults — were confirmed earlier this week.
The case announced Thursday is an adult. Health officials say there is no connection between the five cases and that all five are from different families.
The statement from Toronto Public Health notes that none of the five patients confirmed to have measles have travelled recently.
"This indicates measles is currently circulating in Toronto," reads a Toronto Public Health statement.
The statement re-iterated the importance of vaccination for measles.
"Two doses of MMR (mumps, measles, rubella) vaccine will provide full protection for over 95 per cent of people ... if the public is unsure of their immunization status, they should contact their health care provider."