With increased emphasis on accessibility and quality education in tertiary institutions, open and distance learning (ODL) is occupying the center stage in Nigeria. Open educational resources (OERs) is becoming a valuable alternative to improving access to high-quality educational content released under open licenses by outstanding universities worldwide. Some conventional universities in Nigeria now offer both face-to-face and ODL courses, making them dual-mode. However, the universities who employ this dual-mode system are faced with the challenges of developing viable ODL courses. This study examined the extent the courseware developers in these universities in Nigeria use and publish their courses as OER and barriers to the effective utilization and publishing of OER especially in their institutional repositories (IR). The research instrument was designed as a descriptive survey. The sample for the study consists of 73 courseware developers selected from four dual-mode universities in Nigeria. The findings of the study showed that course developers in dual-mode universities do not use OER to a high extent nor publish OER to a high extent in their IR. It was observed that they experience more barriers with publishing of OER than with use of OER. Among others, it is recommended that there should be more awareness around this framework and course developers should be encouraged through incentives for greater participation in the use and publishing of OER in IRs.