After premature closures in 2004 of biomedical human immunodeficiency virus (HIV) prevention trials involving sex workers in Africa and Asia, the Joint United Nations Programme on HIV/AIDS (UNAIDS) and Global Advocacy for HIV Prevention (AVAC) undertook consultations to establish better participatory guidelines for such trials in order to address ethical concerns. This study investigated sex workers' knowledge and beliefs about research ethics and good participatory practices (GPP) and the perspectives of sex workers on research participation. A 33-question survey based on criteria identified by UNAIDS and AVAC was translated into three other languages. Participants were recruited through mailing lists and contacts with existing sex work networks. In total, 74 responses from Europe, the Americas and Asia were received. Thirty percent of respondents reported first-hand involvement in biomedical HIV prevention trials. Seventy percent indicated a lack of familiarity with codes of ethics for research. This paper focuses exclusively on communication issues described in survey responses. Communication was an important theme: the absence of clear communication between trial participants and investigators contributed to premature trial closures in at least two sites. Sex workers had recommendations for how researchers might implement GPP through improved communication, including consultation at the outset of planning, explaining procedures in non-technical terms and establishing clear channels for feedback from participants.