The aims of this study is to carry out a long-term follow-up evaluation of a well-established therapeutic community treatment for addictions in Navarre (Spain) and to make a comparison between the program completers and the dropouts, as well as between relapsing and nonrelapsing patients, on a broad set of variables. A long-term follow-up design (mean of 6 years after leaving treatment) was used to analyze the outcomes of the therapeutic program. The sample consisted of 155 subjects (113 completers and 42 dropouts). A personal interview was carried out with each one of the located subjects. The interviews took place between September 2000 and September 2004. Treatment "dropouts" manifested a higher and earlier rate both of relapses, and of new treatments for their drug addiction than the completion group. The program was also effective in reducing criminal behavior and improving the state of health. Significant differences were found across outcome variables when comparison was made between treatment completers and "dropouts." All subjects improved on outcome variables after receiving the treatment. When relapsing and nonrelapsing patients were compared, significant outcome differences were also found between groups. The study's limitations are noted and future needed research is suggested.