A research survey was designed to investigate the factor affecting participation of illiterate adults in adult education in Kenya and suggests ways to improve on the literacy levels. From the findings it was established that lack of conducive learning environments for adult learners, unavailability of enough instructional materials, negative attitude towards learning and shortage of professionally trained trainers for adult learners were some of the factors hindering many illiterate adults from participating in adult education programmes. It was recommended that the government and other agencies should take more responsibility in supporting adult education to make it more attractive to adult learners to attend the programmes by providing adequate funding and facilitating teacher training. The need for effective involvement of the learners in curriculum developed was emphasized.