In human service agencies, situations exist at various times in which consumers are not familiar with the staff who work with them. We evaluated effects of familiar versus unfamiliar staff working with two men with severe disabilities in a vocational program. Results indicated both participants displayed more compliance with familiar staff relative to unfamiliar staff and one exhibited more on-task (one was near ceiling levels with both staff). Subsequently, a familiarization process was conducted with four new staff before working with four men with severe disabilities that involved spending time with a participant in a preferred activity and phasing in to the participant's routine. Each staff worked with one participant after being familiarized and concurrently with another without being familiarized. In all but one case, participant compliance was greater with the familiarized staff. Except when on-task was near ceiling levels, it also was higher with the familiarized staff. Additionally, results offered some support for the existence of a good relationship between familiarized staff and participants in terms of more participant happiness indices than with unfamiliar staff and, to a smaller degree, less unhappiness indices and problem behavior. Implications for practitioners are discussed, including being aware of potential problems when unfamiliar staff work with adults with severe disabilities and considering familiarizing new staff prior to working with individuals. Discussion also addresses how more attention could be directed to relationship development from a practitioner and research perspective.