The evaluation of repeated annual treatment with ivermectin in onchocerciasis-endemic communities using output indicators such as acceptance rate (AR) and community compliance rate (CCR) are invaluable tools for assessing community response to onchocerciasis control measures. These indicators were employed in evaluating the responses to annual ivermectin treatment in ten communities in Lade District, Kwara State, Nigeria, where annual ivermectin treatment had reached the fourth round in 1995. The mean AR in all of the communities at the first round of treatment (Tx1) was 95.18% while the mean for Tx1-Tx4 varied between the communities and ranged from 62.82% to 98.49%. The CCR also differed between the communities and ranged from 38.56% to 96.97%. Adverse reactions to ivermectin treatment at Tx1 brought about non-compliance in Lile (CCR of 38.46%), one of the communities studied. AR in Lile also decreased from 94.87% at Tx1 to 61.54% at Tx2, 53.85% at Tx3 and 41.03% at Tx4. (The commencement of community mobilization in defaulting communities after Tx4 restored the acceptance at the next round of annual treatment. The drop in participation in Lile due to adverse reactions would have been averted if annual ivermectin treatment were properly monitored. This study advocates the need for the continuous monitoring and evaluation of onchocerciasis-endemic communities currently receiving treatment, especially in the implementation of the Community-Directed Treatment with Ivermectin (CDTI) programme, so that feedback from the communities can permit proper intervention if necessary.