Levodopa has played a central role in the treatment of Parkinson's disease for nearly 40 years and remains the single most effective symptomatic treatment for the disease. However, the response to levodopa therapy changes over time, and its long-term use is commonly associated with disabling motor complications. For this reason, the appropriate role of levodopa in the treatment of Parkinson's disease—in particular, the question of when to initiate therapy with the drug—has been a matter of controversy. Because levodopa is the most effective treatment for Parkinson's disease, the management of this disease becomes a matter of balancing short-term symptom control with long-term functional outcomes. This article provides an overview of the basis for levodopa-associated motor complications and their impact on patients' clinical function and quality of life, followed by a discussion of strategies for managing these complications to achieve optimum symptom control while minimizing the adverse effects of long-term therapy.