The recovery data of 40 doping agents from human urine were evaluated. Retention data were standardized by the calculation of relative retention times using N,N-diisopropyl-n-dodecane as the internal standard. The relative standard deviations of retention times were less than 0.5% for the within batch analyses and less than 0.8% for the day-to-day analyses. Good recoveries (greater than 70%) were observed for most of the drugs.