The research reveals that the concept of resilience is a useful tool for understanding the impact of repressive policies on illegal drug markets. The data demonstrate that most illegal drug markets shared the characteristic of resilient systems: they had low vulnerability to external shocks, they recovered fairly well after law enforcement interventions, and market participants showed high adaptive capacity when needed. Most illegal drug markets have low-level centralization which reduces the destabilizing effects of an enforcement operation, facilitates the easy replacement of any removed participants, and allows for each dealer or group to adapt to the new situation and reestablish their markets. The framework illustrates that not all illegal markets show the same potential for resilience, and that they could be classified according to their specific combination of resilient properties. The results also provide an illustration of some of the perverse effects of repressive policies and drug law enforcement; the most important consequence of a tough repressive policy being the forced expansion of the pool of individuals who become drug dealers. The more individuals that are arrested in the market, the more the need for additional individuals to replace them increases, which invites more people to join the trade; the larger the quantity of drugs seized by enforcement operations from the market, the higher the incentives to produce and sell more drugs to compensate for these losses. Rather than preventing drug crime, police efforts might be increasing business opportunities and growth for the illegal economy. The findings suggest the need for further research using the concept of resilience to further analyze the threshold over which more arrests will simply produce more harm than it would help prevent. 1 figure