Current regulatory hurdles, the withdrawal of several drugs due to safety concerns, modest weight-loss efficacy using existing drugs and the lack of reimbursement in the US has resulted in limited investment in research and development of anti-obesity drugs by pharmaceutical companies. This has resulted in a limited range of treatment strategies for obese patients. The recent registration of lorcaserin (a 5-HT2C receptor agonist) and Qsymia (a combination of phentermine and topiramate), and the progression of the late-stage drugs liraglutide and NB32 may provide the backdrop for reinvestment to occur. Unlike many other therapeutic areas, preclinical models of obesity have a high degree of predictive validity for efficacy in the clinic and are of value in the discovery of novel compounds and their progression from research into the clinic. Although clinical trials for obesity drugs are of long duration with large patient cohorts required, recruitment is not an issue and end-points e.g. BMI are straightforward to measure. The emergence of new weight-loss agents that also treat diabetes, a co-morbidity associated with obesity, may provide improved treatment strategies. Importantly, even limited success of such drugs is likely to stimulate a marked increase in research and development as obesity is showing no sign of decline.