Mickelson said last month at the U.S. Open, where he was runner-up for a record fifth time, it was "highly unlikely" he would play at Turnberry next week.
His wife, Amy, had surgery July 1 for breast cancer and they are still waiting to decide the best treatment. While his wife was ready to have surgery, Mickelson learned his mother also had been diagnosed with breast cancer.
"As a professional golfer, competing in major championships and winning them is my main objective," Mickelson said on his Web site. "But I've always said family is my No. 1 priority. For that reason, I won't be playing the British Open at Turnberry next week."
He will be replaced in the field by Ben Crane. The alternate list is based on this week's world ranking of players who were not already eligible. Steve Marino becomes the first alternate.
Mickelson did not reveal much about his wife's surgery, although the fact they waited until after the U.S. Open is regarded as a good sign that it was caught early. His mother was to have surgery Friday in Houston.
"It's a trying time for us as we await more test results, but we have excellent medical attention and care," Mickelson said. "We've received wonderful support from so many people, many of whom have gone through the same battle, and we're optimistic, as always."
A three-time major champion, Mickelson has competed in every major since the 1994 U.S. Open, after missing the Masters that year when he broke his leg skiing. Next on the list is Vijay Singh, who will be playing in his 61st straight major at Turnberry. Jack Nicklaus holds the record of 146 straight majors from 1962 to 1998.
