Two-time champion Mark Williams will not play at the Crucible after losing in the final qualifying round to England's Stuart Carrington.
Williams lost 10-7 in the final qualifier after trailing 6-3 from the morning session and was one of five Welsh players to exit at Pond's Forge.
Williams' defeat means he misses out on a place at Sheffield's Crucible for the second time since his debut in 1997.
He also failed to qualify in 2014 when he was beaten by Alan McManus.
Jamie Jones lost 10-8 after leading overnight against Scotland's 2006 world champion Graeme Dott.
Both Michael White and Dominic Dale were also knocked out in the final qualifying stage, Dale losing 10-5 to Belgium's Luca Brecel and White was defeated 10-3 by Englishman Gary Wilson.
Newbridge's Lee Walker, who beat Reanne Evans in the second round, lost to Thailand's Noppon Saengkham 10-8 to complete a disastrous day for Welsh players.
Ryan Day will be the only Welshman at this year's World Championships. It will be the first time there has only been one Welsh player at the event since it was first held at the Crucible in 1977.