In order to identify the necessary information of biochemical Indices for renal effect of lead for the early detection in medical surveillance of lead worker, the reference values of urinary N-acetyl-$eta$-D-glucosaminidase (NAG) activities were studied with 205 office workers in one industrial complex area who were not exposed to lead occupationally. While study variables selected for lead exposure were blood lead (PbB), blood zinc protoporphyrin(ZPP) and $delta$-aminolevulinic acid (DALA) in urine, those for renal effect were urinary N-acetyl-$eta$-D-glucosaminidase (NAG), blood urea nitrogen (BUN), serum creatinine(Cr), serum uric acid (Ua), and urinary total protein(U-TP). The results obtained were as follows: 1. The mean values of blood lead, ZPP and DALA in all subjects were $14.39{pm}4.02{mu}g/dl,;21.61{pm}8.00{mu}g/dl,;and;2.73{pm}0.90mg/l$ respectively. 2. The mean value of urinary NAG activities in all subjects was $3.51{pm}2.01U/l$. The mean value of urinary NAG activities, which calculated from NAG activities divided by urinary creatinine concentration (CNAG), was $5.42{pm}5.53U/g$ creatinine and log-arithmic normal distributed. 3. The reference value of urinary NAG activity was 12.06 U/g creatinine(95% CU=10.57-14.76 U/g creatinine). 4. Logarithmic CNAG(r=0.781 p<0.0l), U-TP(r=0.670 p<0.01) and ZPP(r=0.172 p<0.05) showed statistically significant correlation with CNAG.