Bob Weir, the guitarist who co-founded the Grateful Dead, has died aged 78.

Weir, a cornerstone of the California psychedelic rock group and many of its offshoots, passed away after a battle with cancer and lung issues, according to a post on his Instagram.

There is no final curtain here, not really. Only the sense of someone setting off again, the post says, noting his hopes that his legacy and lengthy catalogue will live on.

The post says he transitioned peacefully, surrounded by loved ones.

He often spoke of a three-hundred-year legacy, determined to ensure the songbook would endure long after him, the post continues. May that dream live on through future generations of Dead Heads.

With a career spanning more than 60 years, Weir's big break was in 1965 with the founding of the Grateful Dead. They quickly became pivotal in San Francisco's counterculture, their style melding psychedelia with American folk influences.

The Grateful Dead was not only a household name but also a pioneer of the jam band scene, known for their extended live performances that blended various genres of music.

The group was inducted into the Rock and Roll Hall of Fame in 1994 and received a Lifetime Achievement Award from the Grammy Awards in 2007.

Despite disbanding in 1995, following the death of fellow co-founder Jerry Garcia, Weir remained active in music through various projects, including Dead & Company, which had a residency at the Las Vegas Sphere in 2024 and 2025.

Diagnosed with cancer in July, he continued to perform even during treatment. Those performances, emotional and soulful, were not farewells, but gifts, the post noted, highlighting his resilience.

His family asked for privacy but expressed gratitude for the outpouring of love and remembrance from fans and fellow musicians.

Tributes flowed in following the announcement of his death. The Empire State Building illuminated in tie-dye colors to honor Weir, and fellow musicians shared heartfelt messages celebrating his influence and spirit.

Former Eagles guitarist Don Felder noted the impact Weir had on him, sharing fond memories of their time together.

Weir's former publicist remarked on his unique sense of humor and passion for music, emphasizing that he dedicated his life to performing until the very end.