YouTube (YT) is the largest global digital video information and communication technology (ICT) channel and has become an important channel for companies and their brands to reach younger target markets with their marketing communications (MC). The main objectives of this research are to determine the effect of YouTube marketing communications (YTMC) on traditional and non-traditional attitudinal relationships, and to establish whether demographic variables and usage factors have an effect on traditional attitudinal relationships among the South African millennial cohort. A multi-stage sampling method was employed and 1,900 millennial cohort members (aged 18-32 years old) participated in the survey. Structural equation modeling (SEM) was used to assess the hypothesized attitudinal relationships. The study found that YTMC had a positive effect on all of the traditional (and one non-traditional) attitudinal relationships. The most favorable attitudinal responses were evident among older age categories, White ethnic groups, access via computer and mobile devices, longer usage length (in years), lower log-on frequencies, and higher log-on duration. Organizations should review their YTMC strategies to take cognizance of the positive attitudinal relationships and demographic variables and usage factors identified by this research when targeting millennial consumers.