This report analyzes 35 less developed countries' (LDC's) exports of high-value and processed agricultural products (HVP's) during 1970-87 and the roles of supply and demand factors in accounting for their export performance. HVP's accounted for 83 percent of LDC agricultural exports. Processed exports have undergone the most rapid growth and accounted for almost half of LDC high-value exports in 1986-87. Developed countries remained the major HVP export market for LDC's. The LDC share of this market fell during 1970-87, although their share of developed-country imports of highly processed HVP's increased. Domestic policies favorable to exports distinguished successful and unsuccessful LDC exporters. Several of the most competitive LDC exporters also adopted policies that promoted exports of specific HVP's. Favorable domestic conditions were not sufficient. Strong developed-country demand was also necessary for successful HVP export performance by LDC's.