The HIV epidemic in the Baltic countries started about the same time. However, the prevalence of HIV in the general population and high risk groups is different. In all countries, the second decade of HIV epidemic was driven by PWID. The spread of HIV through bridging groups to the general population in EE and LV started earlier than in LT. The example of the Baltic countries shows that if there is no adequate and timely response to the problem of drug addiction (especially in prison settings) the HIV situation can change very quickly. It is natural that after having reached its peak, HIV incidence starts declining. However, since far more people have sex (including MSM) than inject drugs, even if sexual transmission is less infectious, then if not properly managed, this may eventually lead to a high number of new infections.