Dopamine agonists have been widely used as add-on to levodopa in the treatment of Parkinson’s disease with motor fluctuations. However, the use of dopamine agonists in early Parkinson’s disease and levodopa-naive patients is controversial. Although dopamine agonists have been compared with levodopa, no studies exist which directly compare one dopamine agonist with another. This evidence-based review compares the results of large published studies of early treatment of Parkinson’s disease with dopamine agonists (cabergoline, ropinirole or pramipexole) with similar studies using levodopa.