Statistics released today by the Irish Turf Club revealed riders were drug-tested on 75 occasions last year and all tests were negative.
A total of 3,120 samples were also taken from racehorses for analysis, and 12 tests were positive.
Turf Club chief executive Denis Egan said: “I am delighted that all samples taken from the 140 riders sampled since testing commenced in May 2003 were negative.
“This is a great achievement, bearing in mind that the Turf Club has adapted the full World Anti-Doping Agency list of prohibited substances and methods.
“The number of horses drug-tested increased by 286 as a result of increased testing at point-to-points.”
Other key points showed that stewards’ inquiries on Irish racecourses rose by 127 to 981 last year, and Appeals and Referral Committee hearings were 64% higher than 2003, with 54 cases being dealt with.
Fallers in jump racing decreased by 2.8% to 847, even though the number of runners increased by 6%.
Egan said: “Most of the statistics are broadly in line with previous years, with one or two exceptions.
“The Appeals and Referrals Committee had a particularly busy year dealing with 54 cases, of which 15 were appeals against the decisions of the acting stewards. This, however, represented only 1.5% of all cases dealt with on the track.”