The purpose of this study was to investigate weight loss expectations and goals in a population sample of US adults who planned to make a weight loss attempt, and to examine predictors of those expectations and goals. Participants were 658 overweight and obese adults (55% women, mean age = 47.9 years, BMI = 31.8 kg/m(2)) who responded to a telephone survey about weight loss. Respondents reported weight loss expectations (i.e., reductions they realistically expected) and goals (i.e., reductions they ideally desired) for an upcoming "serious and deliberate" weight loss attempt. They also reported the expectations they had, and the reductions they actually achieved, in a previous attempt. Respondents' weight loss expectations for their upcoming attempt (8.0% reduction in initial weight) were significantly more modest than their goals for that attempt (16.8%), and smaller than the losses that they expected (12.0%), and achieved (8.9%) in their most recent past attempt (Ps <or= 0.003). Women and participants with higher BMIs had greater weight loss expectations and goals. After controlling for BMI, age, and gender, previous weight loss was unrelated to expectations (but was inversely related to goals) for the upcoming weight loss attempt. Results suggest that overweight and obese individuals can select realistic weight loss expectations that are more modest than their ideal goals. BMI and gender appear to be more important than previous weight loss experiences in determining expectations among persons planning a weight loss attempt.