A rescheduled date has not yet been announced.
He was performing "Dancing on the Ceiling" Wednesday night in Saint Paul, Minnesota when he had to sit down because he was feeling dizzy.
The singer went on to perform "Three Times a Lady" before he walked back stage for intermission and did not return.
"Under advisement by doctors to rest and return to full health, Lionel Richie has postponed his next two shows on Friday, June 26 in Chicago, IL and Saturday, June 27 in Columbus, OH," a statement from Live Nation obtained by ABC7 Chicago read. "He and Earth, Wind & Fire will return to the stage on Tuesday, June 30 in Pittsburgh, PA. Lionel is heartbroken to postpone these two shows and cannot wait to be back performing for his fans. We apologize for any inconvenience this causes fans who have tickets for these two shows. Rescheduled dates will be announced soon."
His camp hasn't revealed a diagnosis, but Richie was reportedly taken to the hospital as a precaution.
The concert was the first performance in a tour with Earth, Wind & Fire. The band's drummer said Richie was suffering from dehydration.
CNN contributed to this report.