Commercial motorcycle (CM) accidents constitute a major public concern in Nigeria. There is 8:10 chance that injuries resulting from these accidents are severe and debilitating including head and spinal injuries. This study is aimed at producing useful data on the prevalence, frequency, and determinants of helmet use among commercial motorcyclist in Ido-Osi Local Government Area, Ekiti State, Nigeria. The study was a descriptive/cross-sectional study. A total of 360 respondents were selected by multi-stage sampling technique and interviewed using assisted self-administered, semi-structured questionnaire. Data were analyzed using SPSS version 21. Determinants of helmet use examined included age, educational level, marital status and religion. There was a 100% response rate. More than half of the respondents were within the age range of 20-29 years 164(53.6%) with the mean age of the study participants 29.9. The prevalence of helmet usage among commercial motorcyclist was 23.5%. The commonest reason for not using a crash helmet in this study was non-availability. The commonest reason for the non-availability of the welding helmet was the cost of the helmet. Less than half of the respondents were able to show or present helmet although some of the helmet presented were sub-standard (39.7%). The study also revealed irregular use of helmets among the respondents that used a helmet while riding a motorcycle as only 2.7% of them used it for all the five riding sessions assessed in this study. There was a statistically significant relationship between age, educational level, marital status and the use of helmets among respondents with p values of 0.005, 0.027, and 0.009, respectively. The prevalence of the use of helmets among the motorcyclist in this study is low despite the high level of awareness of legislation among the respondents on the use of helmets during riding. There is a need for the government to make provision for a safety helmet for this group of people at a subsidized rate if it cannot be given free of charge because of the economic situation of the country. There is a need to carry out behavioral change communication for this group of people.