Present experiment was performed to establish the optimal reaction conditions for measurement of urinary gamma-glutamyltranspeptidase(${gamma}$-GTP), N-acetyl-${eta}$-D-glucosaminidase (AGS) and alanine aminopeptidase(AAP) activities in bovine and to investigate in vitro stability of the enzymes, within-run imprecision of the methods, and normal ranges. 1. The optimal wavelength for measurement of ${gamma}$-GTP activity was 545nm. 2. The optimal pH of Tris-HCI buffer containing glycylglycine for measurement of urinary ${gamma}$-GTP activity was 7.6～7.8(37$^{circ}C$). 3. Coefficient of variance for within-run imprecision of urinary ${gamma}$-GTP activity ranged from 4.8 to 7.2% and there was no significant difference among replications, 4. The optimal wavelength for measurement of urinary AGS activity was 405nm. 5. The optimal pH of citrate buffer for measurement urinary of AGS activity was 4.0(37$^{circ}C$). 6. Coefficient of variance for within-run imprecision of urinary AGS activity ranged from 3.9 to 6.1％ and there was no significant difference among replications. 7. The optimal wavelength for measurement of urinary AAP activity was 400nm. 8. The optimal pH of phosphate buffer for measurement of urinary AAP was 7.8. 9. Coefficient of variance for within-run imprecision of urinary AAP activity ranged from 2.5 to 4.8% and there was no significant difference among replications. 10. ${gamma}$-GTP and AGS activities were increased significantly by gel-filtration. 11. Turbidity interfered with measurement of urinary AAP activity in bovine unless the specimen was gel-filterated. 12. Preservation of the specimen at 5$^{circ}C$ or -20$^{circ}C$ did not affect the AGS activity at least for 7 days after collection. 13. Preservation of the specimen at 5$^{circ}C$ or 20$^{circ}C$ did not affect the ${gamma}$-GTP and AAP activities statistically, but some individual specimens revealed fluctuation during preservation. 14. ${gamma}$-GTP, AGS and AAP activities revealed fluctuation by the tine of the day when the specimen was collected. 15. The normal ranges of urinary ${gamma}$ -GTP, AGS and AAP activities were 6.60${pm}$3.26(2.36-14.50), 1.31 ${pm}$ 0.81(0.33-3.78), and 1.73 ${pm}$ 0.55(0.77-3.03)U/l. respectively.