Objective: To measure the impact of a state health department policy to provide allied health professional staff with access to a point-of-care, 24 h, online evidence system in terms of awareness, use and clinical impact of the system on clinical practice; to identify perceived barriers to use, and differences in measures between seven professional groups (physiotherapists, occupational therapists, speech pathologists, dieticians, clinical psychologists, pharmacists and social workers). Method: A convenience sample of 790 allied health professionals from 65 randomly selected hospitals in New South Wales, Australia. A self-administered questionnaire was distributed. Rates of use, frequency and types of resources accessed were calculated. Comparisons between professional groups were undertaken using Chi-square analyses and t-tests. Results: The results showed that 82% of allied health professionals had heard of the online evidence system, and of those 76% had used it. Pharmacists had the highest rates of use and social workers the lowest. Of users, 90% agreed that use of the system had the potential to improve patient care and 45% reported direct experience of this. Computer skills and easy access were significantly associated with use and frequency of use. Among non-users, lack of specific training in the use of the online evidence system and lack of time were the most frequently reported reasons for not using the system. However, among users there was no relationship between this training and the frequency or effectiveness of use, i.e. the ability to find the information required. Conclusions: Allied health professionals will use an online evidence system when it is provided, however there are marked differences in use by professional groups. General training aimed at improving computer skills appears more important in encouraging use of an online evidence system, than specific system-based training. Perceptions of organisational and professional support for allied health professionals to use online evidence as a legitimate part of their work play an important role in influencing system use.