Sjögren's syndrome is a chronic autoimmune disorder characterized by lymphocytic infiltration, and consequently hypofunction of lacrimal and salivary glands. The loss of salivary function induces oral dryness (xerostomia). This review focuses on methods for determining salivary gland function including clinical signs, salivary flow rate measurements (sialometry), analysis of salivary composition (sialochemistry), histopathological and radiologic examinations, and other recent advanced techniques.