Group One-winning trainer Barry Miller has died in Brisbane after a long illness.

Miller, 78, trained about 1000 winners on tracks all over Australia, the best being Show A Heart.

The trainer and his younger brother Trevor were dominating figures in Queensland racing for three decades after starting their careers at Cunnamulla in the western part of the state.

Barry Miller enjoyed his biggest successes with Show A Heart who won the Group One TJ Smith Classic in 2000, the Caulfield Guineas later that year, the Toorak Handicap in 2001 and went out a winner of the 2002 Stradbroke Handicap.

Show A Heart stood at GlenloganPark in Queensland and his progeny includes Group One winners Heart Of Dreams, Woorim and Toorak Toff.

Miller first came to prominence when 100-1 chance Casca almost ran down champion Manikato in the 1979 Doomben 10,000.

He often said that second place put him on the map in Brisbane.

His other good horses included Forest Jim, Big Rhumba, Madam Zoffany, Miss Sandman, Happy In The Red and Marcelo.

Close friend and fellow trainer Pat Duff said Miller should be remembered as one of Queensland's greats.

"He was noted for getting his horses fit which is why they were so good on wet tracks," Duff said.

Trevor Miller said his brother had been ill for some time.

"He was doing it tough the last 18 months but he will be remembered as a true horseman," he said.

Barry Miller's funeral will be held next week to allow some family members to travel from overseas.