The day after the comedienne's daughter dedicated an entire episode of Fashion Police to her mother in the form of highlight reels from past shows, Rivers said "it's been difficult" living without her mom.
"Today marks one year since my mother passed," the 47-year-old television personality wrote. "This was the year of firsts: first holidays, first birthdays, first everythings without mom, without grandma. While it's been difficult, I've been amazed by the outpouring of love and overwhelming kindness we've received from family, friends and people whose lives were touched by the woman they knew as Joan -- a woman we all miss so very much."
The message has been retweeted over 700 times and favorited by over 1,700 Twitter users.
Joan Rivers died Sept. 4, 2014 after complications from a routine surgery done in August left her in a medically-induced coma. Melissa chose to take her mother off life support during her stay at the Mount Sinai Hospital in New York.
"It is with great sadness that I announce the death of my mother Joan Rivers," Melissa said in a statement at the time. "She passed peacefully at 1:17 p.m. surrounded by family and close friends. My son and I would like to thank the doctors, nurses and staff of Mount Sinai Hospital for the amazing care they provided my mother."
"My mother's greatest joy in life was to make people laugh," she continued. "Although that is difficult to do right now, I know her final wish would be that we return to laughing soon."
Since her mother's death, Melissa launched an investigation against the clinic which performed the initial surgery and sued them.
She also brought back Fashion Police after a messy shuffle between co-hosts Giuliana Rancic and Kelly Osbourne regarding comments Rancic made about singer Zendaya's hairstyle at the Academy awards earlier this year.
"My biggest complaint was the feeling that she kind of [expletive] all over my mother's legacy in her statement on leaving," she said of Griffin's departure at the time. "And I know that that was not an intentional reading of it, but that's how I felt."