Summary: The United States has been providing assistance to Colombia since the early 1970s to help the Colombian National Police and other law enforcement agencies, the military, and civilian agencies reduce illegal drug production and trafficking. Recognizing that illegal drug activities are a serious problem, the Colombian government announced a counternarcotics plan known as Plan Colombia. This testimony reviews the U.S. counternarcotics efforts in Colombia. Although U.S.-provided assistance has enhanced Colombian counternarcotics capabilities, its usefulness has sometimes been limited because of long-standing problems in planning and implementation. For example, little progress has been made in launching a plan to have Colombia's National Police assume a larger role in managing the aerial eradication program, which requires costly U.S. contractor assistance. The governments of the United States and Colombia face continuing and new financial and management challenges in implementing Plan Colombia. The costs and activities needed to implement the plan are unknown at this time, and it will take years before any significant reduction in the drug trade is seen. Colombia must resolve problems with its political and economic stability and improve its management of counternarcotics funding in order to successfully implement Plan Colombia. The testimony summarized the October report, GAO-01-26.