Background The prevalence of sexually transmissible infections (STIs) is increasing among older Australian women, partly due to re-partnering after divorce or death of a spouse. Older women may be less likely to use condoms with new sexual partners, exposing themselves to STIs. An online survey compared characteristics of internet dating women aged 40 and above with 18 to 39 year olds, and determined the factors associated with protective safer sex attitudes. Methods: An email directed women who had logged onto the internet dating service ‘RSVP’ in the previous 6 months to a survey hosted by Family Planning New South Wales. The survey explored demographic factors, STI-related knowledge and attitudes towards safer sex practices. Factors associated with discussing STIs before sex and refusing sex without a condom with a new partner were analysed using logistic regression. Results: The questionnaire was completed by 1788 women. Almost two-thirds (62.2%) were aged 40 or over. The majority (64.8%) were seeking a long-term partner. In the previous year, 41.5% of all women met a new sexual partner via the internet. Women aged >40 years were significantly more likely to discuss STIs with a new partner but less likely to refuse sex without a condom compared with younger women. Conclusions: The internet is a useful venue for women of all ages to meet new sexual partners. Older women are vulnerable to STI acquisition through failure to use condoms with a new partner. Research is needed to determine effective interventions to increase condom use in this age group.