Objective To determine women's preferences for and reported experience with medical test decision-making. Design Computer-assisted telephone survey. Setting and participants Six hundred and fifty-two women resident in households randomly selected from the New South Wales electronic white pages. Main outcome measures Reported and preferred test and treatment (for comparison) decision-making, satisfaction with and anxiety about information on false results and side-effects; and effect of anxiety on desire for such information. Results Overall most women preferred to share test (94.6%) and treatment (91.2%) decision-making equally with their doctor, or to take a more active role, with only 5.4-8.9% reporting they wanted the doctor to make these decisions on their behalf. This pattern was consistent across all age groups. In general, women reported experiencing a decision-making role that was consistent with their preference. Women who had a usual doctor were more likely to report experiencing an active role in decision-making. More women reported receiving as much information as they wanted about the benefits of tests and treatment than about the side-effects of tests and treatment. Most women wanted information about the possibility of false test results (91.5%) and test side-effects (95.6%), but many reported the doctor never provided this information (false results = 40.0% and side-effects = 31.3%). A substantial proportion said this information would make them anxious (false results = 56.6% and side-effects = 43.1%), but reported they wanted the information anyway (false results = 77.6% and side-effects = 88.1%). Conclusions Women prefer an active role in test and treatment decision-making. Many women reported receiving inadequate information. If so, this may jeopardize informed decision-making.