A medical questionnaire is a form you complete as part of the application process for an underwritten insurance plan. It asks detailed questions about your current health, medical history, medications, hospitalizations, surgeries, family medical history, and lifestyle factors such as smoking and alcohol use. Your answers are used by the insurer's underwriters to assess your risk and determine the terms of your coverage. It is critical to answer all questions truthfully and completely — providing false or incomplete information can result in claims being denied or your policy being voided entirely, even years later. If you are unsure about a medical detail, it is better to disclose it and let the insurer decide its relevance. Guaranteed-issue plans do not require a medical questionnaire.