The aims of the study were to investigate the effects of the type of track, age, sex and origin of horse on racing time for thy were obtained from Arabian horses, and to estimate the genetic parameters for racing time. The racing records used in I is stud the Turkish Jockey Club. The trait used in the study was racing time for racing distances of 1200 m, 1300 m, 1400 m, 1500 m, 1600 m, 1800 m, 1900 m, 2000 m, 2100 m and 2200 m. The data from each racing distance were analysed separately. Genetic parameters were estimated by REML procedure using the DFREML program. The effects of type of track, sex and origin of horse on racing time were significant for all racing distances. The effect of horse age on racing time was not significant for distances of 1300 m, 1500 m, 2000 m and 2200 m, whereas it was significant for other distances. Estimates of heritability ranged from 0.175 to 0.304, and repeatability ranged from 0.295 to 0.460, depending on the racing distance. These estimates indicated that the genetic progress for racing performance could be achieved if breeders use accurate selection programmes.