The Cook County jury convicted Prentice Phillips, 52, Thursday on two counts of murder in the death of Margaret Blair.
Blair was found beaten, robbed and sexually assaulted in her Rogers Park home after police said an intruder forced his way inside . She later died of her injuries.
Police linked Phillips to the case with DNA collected from the crime scene and processed in 2013 with money from a cold case grant.
Phillips is scheduled to appear again in court in January.