Longterm use of tumor necrosis factor-alpha (TNF-alpha) blocking agents requires ongoing monitoring to confirm efficacy and to avoid drug toxicity. Epidemiologic studies may offer important complementary information about risks and benefits of this class of drugs. The safety profile of biologic therapies includes a wide spectrum of adverse events, of which the most relevant are risk of infections, malignancy, and cardiovascular diseases. The lack of published recommendations on monitoring suggests that clinicians must evaluate the patient for the risk or presence of any adverse events by regular checkups, with careful assessments, for their early detection. The safety profile in regard to psoriatic arthritis is discussed.