Guided by the conceptual framework of the Health Belief Model, this study aimed to identify factors associated with pregnant women's expressed willingness to accept voluntary counselling and HIV-testing (VCT). A cross-sectional interview survey of 500 pregnant women, complemented by focus group discussions, was conducted in the Kilimanjaro region of Tanzania. Constructs derived from the Health Belief Model explained 41.7% of women's willingness to accept VCT. Perceived high personal susceptibility to HIV/AIDS, barriers related to confidentiality and partner involvement, self-efficacy regarding alternative feeding methods and religion were all shown to be associated with willingness to accept VCT. The women's acceptance of VCT seems to depend upon their perceiving that VCT and alternative feeding strategies provide clear benefits, primarily for the child. Whether a positive attitude to VCT and alternative feeding strategies are transformed into actual behaviour depends on a set of complicated decisions in which several potential psychological consequences are assessed. Sharing the diagnosis with partners may not have the intended effect if there is a lack of sensitivity to the women's fear of blame and rejection. If pregnant women are to fully participate in and benefit from mother-to-child-transmission prevention efforts, their partners must be committed and involved in the process.