The Keeping Up With The Kardashians star, who gave birth to son Mason Dash Disick on December 14, 2009, marked the occasion with a blog post called '"Happy Birthday To My Little Angel'.
"You complete and fulfill my life," she wrote on her official website, alongside photographs of Mason taken over the past twelve months.
"This year with you has been more than I could have ever imagined."
The reality star's siblings Khloe and Kim have also taken to their official websites to send birthday wishes to the baby, whose dad is Scott Disick.
"From the moment Mason was born, we were all madly in love with him," wrote Khloe. "It didn't matter that he couldn't talk, walk, or do pretty much anything LOL, his existence in itself enriched all of our lives in a way we never knew possible"
Kim added on her own website: "Words can't express how much little Mase has changed my life. He is such a blessing to our family and watching him grow into a gorgeous little man is so amazing."
