The hard-rocking bandleader most famously fronted an eponymous group in the 1970s that featured future Van Halen frontman Sammy Hagar on vocals, and the group pounded out rock hits such as "Bad Motor Scooter," "Rock Candy" and "Rock the Nation."
Montrose also appeared on Van Morrison's Tupelo Honey and St. Dominic's Preview albums and Edgar Winter Group's They Only Come Out at Night, as well as doing session work with Boz Scaggs, Herbie Hancock and more.
According to a posting on Montrose's website, Montrose had cancer.
"He passed today. He'd battled cancer, and staved off old age for long enough. And true to form, he chose his own exit the way he chose his own life. We miss him already, but we're glad to have shared with him while we could."
The posting also sounded a positive note, suggesting that the rocker had had the chance to speak to those close to him in his final months.
"A few months ago, we held a surprise party for Ronnie Montrose's 64th birthday. He gave an impromptu speech, and told us that after a long life, filled with joy and hardship, he didn't take any of our love for granted."