The growth of the Internet opens new possibilities for web-based data collection in cognitive anthropology. This study examines whether free-list data collected online are comparable to those collected with face to face interviews or with self-administered paper questionnaires. We collected free lists for two cultural domains in the United States: one diffuse (things that mothers do) and one relatively well defined (racial and ethnic groups). We selected a purposive sample of 318 university students and randomly assigned participants to provide free lists for one of these domains using a web-based survey, a face to face interview, or a self-administered paper questionnaire. All three modes identified the same set of salient concepts in each domain. Median list length per respondent varied across modes in response to a standard free-list question and to supplementary probes. For the well-defined domain of ‘‘racial and ethnic groups,’’ supplementary probes widened differences among modes; for the more diffuse domain of ‘‘things that mothers do,’’ probes erased evidence of mode effects. Collecting free lists online is viable but may yield different results depending on the study population and attributes of the cultural domains.