Family health history (FHx) is one of the simplest and most cost-effective and efficient ways to collect health information that could help diagnose and treat genetic diseases at an early stage. This study evaluated the efficacy of collecting such family health histories through a virtual conversational agent (VCA) interface, a new method for collecting this information. Standard and VCA interfaces for FHx collection were investigated with 50 participants, recruited via email and word of mouth, using a within-subject experimental design with the order of the interfaces randomized and counterbalanced. Interface workload, usability, preference, and satisfaction were assessed using the NASA Task Load Index workload instrument, the IBM Computer System Usability Questionnaire, and a brief questionnaire derived from the Technology Acceptance Model. The researchers also recorded the number of errors and the total task completion time. It was found that the completion times for 2 of the 5 tasks were shorter for the VCA interface than for the standard one, but the overall completion time was longer (17 min 44 s vs. 16 min 51 s, p = .019). We also found the overall workload to be significantly lower (34.32 vs. 42.64, p = .003) for the VCA interface, and usability metrics including overall satisfaction (5.62 vs. 4.72, p < .001), system usefulness (5.76 vs. 4.84, p = .001), information quality (5.43 vs. 4.62, p < .001), and interface quality (5.66 vs. 4.64, p < .001) to be significantly higher for this interface as well. Approximately 3 out of 4 participants preferred the VCA interface to the standard one. Although the overall time taken was slightly longer than with standard interface, the VCA interface was rated significantly better across all other measures and was preferred by the participants. These findings demonstrate the advantages of an innovative VCA interface for collecting FHx, validating the efficacy of using VCAs to collect complex patient-specific data in health care.