Levels of fasting blood glucose, serum beta-glucuronidase and beta-N-acetylglucosaminidase in 47 Libyan diabetic patients were determined. The respective mean values were 254.5 +/- 11 mg/dl, 74 +/- 5.7 Sigma units/ml and 171.8 +/- 25.5 microM PNP/dl. The mean body mass index and duration of diabetes of the patients were 30.5 +/- 0.91 kg/m2 and 7.5 +/- 1.16 years, respectively. Statistically significant correlations were found between fasting blood glucose and serum beta-glucuronidase levels (r = 0.65; p less than 0.001) and also between fasting blood glucose and beta-N-acetylglucosaminidase levels (r = 0.58; p less than 0.001). The activities of these two enzymes increase in serum with increasing fasting blood glucose levels. Patients with positive family history of diabetes have higher activities of these two enzymes than those without positive history of diabetes in the family. Patients with secondary complications have both enzymes elevated as compared with patients without secondary complications. Female patients have higher beta-N-acetylglucosaminidase activity and lower beta-glucuronidase activity than males. Age and duration of diabetes do not appear to have any effect on the activities of these enzymes.