Levels of pseudocholinesterase (PsChe) were measured in 20 patients with obsessive-compulsive disorder (OCD) and 20 healthy volunteers. The OCD group had significantly higher PsChe serum activity than in their sex- and age-matched control group. Patients' scores on the Hamilton Rating Scale for Anxiety (HRS-A) and the Beck Depression Inventory (BDI) were not correlated with their PsChe levels. The results provide additional support for the observation of higher PsChe levels among anxiety-related psychiatric conditions. However, the relationships among anxiety, depression, and PsChe appear to be complex. The nature and implications of elevated PsChe levels are still unknown.