The TV personality and author also posted a video on Instagram, breaking down the momentous occasion.
"Thirty-eight years of marriage," said Dr. Phil. "Think about it. That's 13,870 days -- 332,880 hours. That's a lot of smiles."
In April, Robin sat down with New You magazine, opening up about their marriage.
"People cannot understand when we say we don't fight," said Robin. "They go, 'That's just not natural. You're lying! Couples fight.' But we don't fight and it's because we had a conversation early on and I told him that it's not natural for me to be in a house where people are screaming and yelling -- my parents didn't do it, I don't do it and I don't want to live in a house like that. He got it and has never raised his voice around me. We don't fight."