"I believe they've had full access to the courts and full access to have a fair trial, not only in the state system, but in the federal system," said Bush, the GOP presidential candidate, about Texas' death row inmates.
But a report in Sunday's Chicago Tribune found that of the 131 executions in Texas since Bush became governor in 1995, defense attorneys for 40 inmates presented just one witness - or no evidence at all - during the sentencing phase.
Bush countered, "The great thing about America is that people have full access to courts. If you're asking me as to whether or not the innocence or guilt or people have had adequate access to the courts in Texas, I believe they have."
And the Tribune report comes just days after Texas Attorney General John Cornyn announced that he is reviewing nine capital cases in which the jury may have considered race as a factor before delivering a death sentence.
Cornyn's announcement follows a U.S. Supreme Court ruling last week overturning an Argentine man's death sentence because Texas jurors wrongly might have considered his race in determining his punishment.
Victor Hugo Saldano's conviction for the robbing and killing of a man near Dallas in 1995 still stands, but he will receive a new punishment hearing.
Saldano's case led to a review in which Texas uncovered eight more capital murder cases in which an expert witness for the state, psychologist Walter Quijano, testified that race was a factor that jurors should consider in determining whether the defendant be given the death penalty.
Cornyn, a Republican like Bush, said his office had reviewed all executions since the death penalty was reinstated in Texas in 1982 and had not found any cases in which a defendant was executed following such testimony by Quijano.
The state has contacted the defense attorneys and local prosecutors in the eight cases uncovered by the review to determine what further steps should be taken, Cornyn said in a written statement.
"As I explained in a filing before the United States Supreme Court on May 3, it is inappropriate to allow race to be considered as a factor in our criminal justice system," he said.
During the punishment phase of Saldano's trial, Quijano testified that blacks and Hispanics were over-represented in the prison population, and prosecutors said jurors should consider Saldano's Hispanic ethnicity when they decided if he should be jailed for life or given the death penalty.
The frequent use of the death penalty in Texas has come under increasing national scrutiny as Bush seeks the White House.
Texas has executed 218 people since 1982, far more than any other state, including 131 since Bush became goveror in 1995. Bush has reaffirmed his strong support for the death penalty on the campaign trail, and his firm belief that it is applied fairly in Texas.
He has only once commuted a death sentence to life imprisonment, and last week granted a 30-day reprieve for the first time so that a condemned man could undergo a new set of DNA tests.
Death penalty critics, including the American Bar Association, say defendants in Texas capital murder cases are often represented by incompetent, court-appointed lawyers and that the appeals process is slanted toward upholding executions.
In one controversial case, death row inmate Calvin Burdine is fighting to overturn his 1983 conviction on the grounds that his court-appointed lawyer slept through much of his two-day trial.