Due to its serious comorbidities and high prevalence, obesity is one of the heaviest burdens for public health. Although diet, exercise and behavioral modification are the first-line treatment for obesity, their outcomes are not satisfactory. The goal of this article is to review currently available anti-obesity drugs so that physicians may apply the principle of pharmacologic treatment for obesity to obese patients in the real clinical situation. Orlistat, phentermine, diethylpropion, mazindol, and phendimetrazine have been approved as anti-obesity drugs by Korea food and drug administration and administered to patients in Korea. Besides, several non-approved drugs, including fluoxetine, bupropion, topiramate and zonisamide, are being used for weight reduction. Among these drugs, orlistat has been studied most and is the only approved drug for long-term weight management. On the other hand, the rest of the approved drugs lack the evidence of safety issues on the long-term administration. Considering that the non-approved drugs have only a small body of clinical trial results for their efficacy and safety as anti-obesity drugs, it is not appropriate to use them as a first-line therapy in obesity. Because several new medicines and combination therapies are under investigations, more drug therapy options seem to be available in this field in coming years. Although the properly executed pharmacologic treatment is a good option for weight reduction, physicians should recognize that diet, exercise, and behavioral modification are essential to all obese patient and that pharmacologic treatment has several limitations until now.