This paper presents a new hand-gathered database on tariff rates for 18 least developed countries and Korea at the 4-digit level in HS 1988 and SITC revision 2. The database contains one observation per country and per decade starting from the 1970s to 2000/2002. Over time, the tariff schemes of the LDCs follow a symmetric bell-shaped distribution with low rates in the 1970s, which are raised in the 1980s, and then lowered or kept constant in the 1990s and substantially lowered in 2000/02. The analysis in the paper shows that the LDCs have already lowered their average tariff rates to those levels considered 'optimal' by many economists and that they have not shifted the protection over time, keeping the highest rates on labor-intensive and on medium skill manufactures and the lowest rates on mineral products.