In 1981, he lost an 11-year-old son, Jason, to leukemia.
On Sunday, the New York Yankees pitching coach revealed what he has known for a year: He has a form of blood cancer.
"My prognosis is good," Stottlemyre, 58, said. "It's very good."
The reason Stottlemyre went public with his illness is because he will be absent from some Yankees games this season because he has to begin treatment in New York immediately. He won't be at New York's home opener Tuesday.
"There may be some point later in the season when I have to miss a small amount of time," he said.
The cancer Stottlemyre has attacks plasma, the fluid part of the blood, and is called multiple myeloma, a malignant disease of the bone marrow. Philadelphia Flyers coach Roger Neilson has the same cancer and underwent a stem cell transplant last month.
New York manager Joe Torre underwent surgery last year for prostate surgery.
Arizona Diamondbacks pitcher Todd Stottlemyre, one of two surviving Stottlemyre sons, has donated $1 million to leukemia research.
Mel Stottlemyre's announcement came at a news conference at Safeco Field before the Yankees played the Seattle Mariners in the final game of a season-opening road trip.
"I'm at a loss for words," said Roger Clemens, New York's starting pitcher in a 9-3 loss. "When I got to see him, it was after he talked to all you reporters. I just gave him a hug. You don't have anything to say. You're just hoping and knowing he's going to be all right."
The treatment will include four months of chemotherapy.
In Phoenix, Todd Stottlemyre said his father's optimism bolstered the entire family.
"I mean, here he had a son go through a similar deal where leukemia had taken his life, and now to have to battle it in his adult life," he said. "Yet to do it as courageous as he is and with the attitude he is, to me, gives him a fighting chance."
Mel Stottlemyre and his wife, Jean, received the National Recognition Award from the Leukemia Society of America in 1992.
Torre said bullpen coach Tony Cloninger will fill in for Stottlemyre in the opener and whenever necessary for the two-time World Series champions.
Stottlemyre told Torre about his cancer after the manager's operation in March 1999.
"It's a blow and it hits you hard," Torre said. "It's a scary situation whenever you mention cancer."
In his fifth season with the Yankees, Stottlemyre is considered one of baseball's top pitching coaches. His staffs have finished in the AL's top five in team ERA in the past four seasons, including first in 1997 and '98.
Todd Stottlemyre has credited his father's support for his unprecedented attempt to return from a partially torn rotator cuff without surgery.
Todd wanted to see his father immediately, but is scheduled to pitch Monday in San Diego.
"What he said to me this morning was 'Win one for me tomorrow,"' Todd said, choking back tears. "I'd love to get out of here now, but at the same time I know he wants me to stay."
After chemotherapy, Stottlemyre will have a stem cell transplant. He will be treated four days a week for four weeks as an outpatient and not require hospitalization. His blood will be cleansed through a machine and reintroduced in his body, he said.
"The doctors have used the word 'cure,' which I'm very thankful for," Stottlemyre said. "They've told me everything is in my favor.
"It's not painful. There are a few minor side effects from the medication, but it's nothing I won't be able to handle."
He said his condition showed up in a normal physical last spring. He said he was borderline anemic, a blood deficiency. He said he was not fatigued and would not have known about it had he not been diagnosed through blood tests.
"I've kept it quiet for a period of time," Stottlemyre said. "Surprisingly, it hasn't been all that difficult.
"My prognosis is good. It's very good. Like all treatments of cancer, things are changing every day."