DIABETICS ARE GENERALLY CONSIDERED at higher risk for periodontitis than non-diabetics. Among diabetics, those with poorer metabolic control have often been found to have more periodontitis. This study investigated the relationship between two crevicular fluid enzymes, beta-glucuronidase (betaG) and lactic dehydrogenase (LDH), and metabolic control in 93 adults with type 1 or 2 diabetes. Metabolic control was evaluated by glycosylated hemoglobin (HbA1c) levels. The most visibly inflamed site was sampled for crevicular fluid enzymes and plaque for microbial assessment. Plaque, calculus, and probing depth were also recorded. Beta-glucuronidase was found at significantly higher levels in patients with poorer diabetic control while LDH levels were not related to control. Using multiple regression analysis, good metabolic control was the only predicting variable for beta-glucuronidase when considered with microbes, probing depth, plaque, calculus, age, duration, and type of diabetes. If beta-glucuronidase is a predictor of periodontal disease activity, diabetics with poor metabolic control are at higher risk for periodontitis.