Female condom is an effective means of HIV prevention. Monogamous female sexually transmitted infection (STI) patients are exposed indirectly to high risk of contracting HIV/STI via their sole male sex partners. There are few interventions to protect such women whilst female condom use is a potential means of self-protection. With informed consent, this cross-sectional study investigated the prevalence of awareness and acceptability of female condoms among 335 Chinese monogamous female STI patients attending a government STI clinic in Hong Kong. Among those who were aware of female condoms (66.9 % of the sample), 68.3 % were willing to use free female condoms. Awareness was associated with having the sex partner being a boyfriend (OR = 3.76, P < 0.001), knowledge about asymptomatic property of HIV (OR = 2.14, P = 0.006) and no immunity for STI (OR = 2.14, P = 0.011), experience of HIV antibody testing (OR = 2.21, P = 0.004) and unemployment (OR = 0.50, P = 0.011). Among those who had heard of female condoms, acceptability was associated with knowledge about possibility to contracting two STI concomitantly (OR = 2.26, P = 0.03) and perceived chance of contracting STI from the sex partner in the coming 6 months (OR = 2.27, P = 0.04). Awareness is relatively low but the prevalence of acceptability is encouraging. Female condoms have been underused and should be promoted among monogamous female STI patients as a means of empowerment as an option for sex protection.