Victoria MP Denise Savoie, the deputy speaker of Parliament, says she is retiring from politics as of Aug. 31 due to a health warning.
Ms. Savoie, first elected in 2006, declined to elaborate during a news conference at her constituency office on Thursday.
She would only say her doctor recommended a "more balanced lifestyle" after giving her a "health warning."
Ms. Savoie, 69, said the news prompted her to reflect on "the fragility of life," leading to her decision to leave politics.
Federal NDP Leader Thomas Mulcair attended the news conference and paid tribute to Ms. Savoie, a former Victoria city councillor.
"[She] leaves a tremendous legacy to the House of Commons and to the New Democratic Party of Canada," he told reporters, citing Ms. Savoie's work on sustainability and cross-party co-operation.
She said she expects some "great, exciting candidates" will seek the NDP nomination in the by-election that will now have to be called.