The aim of the present study was to assess the impact of the universal salt iodisation legislation on I levels of salt at household, retail and entry level in Lesotho. We used a multistage proportion to population size method to select thirty-one clusters from all the districts and ecological zones of Lesotho. In each cluster, thirty households were randomly selected and salt samples were collected. Six salt samples from two randomly selected retailers in each cluster, and a total of 107 salt samples from all the commercial entry points in the country were also collected. Lesotho does not produce salt and it imports almost all its salt from South Africa. The salt samples were analysed using the iodometric titration method. The median I concentration of salt was 36.2 ppm at entry point, 37·3 ppm at retail level and 38·5 ppm at household level. At household level only 1·6 % used non-iodised salt and 86·9 % used adequately iodised salt. Of all salt collected at household level, 20·4 % was coarse salt, which was significantly less well iodised than fine salt. The study demonstrates a major achievement in the availability of iodised salt as well as household use of adequately iodised salt. Under-iodisation of coarse salt and non-uniformity of salt iodisation at the production site were observed. Therefore, there is a need for enforcement of the salt iodisation legislation especially at entry-point level to ensure that only iodised salt enters the country. During enforcement more emphasis should be given to iodisation of coarse salt.