The rapid assessment procedure for loiasis (RAPLOA) was used to assess the prevalences of loiasis among 4800 subjects in 60 villages in Ondo state, south-western Nigeria. Coverages for community-directed treatment with ivermectin (CDTI) were assessed in the same communities, which were located in the Owo, Akure North, Ifedore, Akure South, Ondo East and Ondo West local government areas (LGA). In addition, fingerprick blood samples were collected from 80 individuals in each of six villages (i.e. one village in each LGA investigated) and checked for Loa loa microfilaraemia. Microfilaraemias were only detected in three of the villages where blood samples were collected and then only at low prevalences (1.25%-5.0%) and intensities (267-1600 microfilariae/ml). No serious adverse events were or ever had been related to the CDTI but mild or moderate adverse reactions were quite common, especially in Akure North (55.0%) and Owo (40.2%). A female subject was more likely to report an history of eye worm than a male subject (20.3%-35.7% v. 20.8%-26.5%, according to LGA). Although the subjects aged 41-50 years formed the age-group most likely to report an history of eye worm (32.7%), the highest CDTI coverage was recorded in the subjects aged 61-70 years (54.7%). The results indicated that CDTI had helped to reduce the prevalence and intensity of Loa microfilaraemia and that ivermectin can continue to be used for mass administrations in Ondo state with little risk of serious adverse events.