Sampling lesbian, gay, and bisexual (LGB) people to recruit a national probability sample is challenging for many reasons, including the low base rate of LGB people in the population. To address this challenge, researchers have relied on diverse approaches to sampling LGB people. We aimed to test an innovative method to assemble a U.S. national probability sample of non-transgender sexual minority adults. Our approach used two phases. In Phase 1, we identified LGBT respondents in a probability general population sample. These respondents were then queried about their sexual orientation and gender identity using short screening questions to identify non-transgender sexual minority respondents. In Phase 2, the identified sexual minority respondents completed the targeted survey online or on a mailed questionnaire. In Phase 1, using random-digit dialing, a nationally representative sample of 366,644 respondents were screened in a brief telephone interview. Of them, 3.5% ( = 12,837) identified as LGB or transgender. In Phase 2, eligible respondents were asked to participate in a self-administered survey questionnaire. Eligibility was based on gender identity, age, race and ethnicity, and educational restrictions. Of the 3525 who were eligible, 81% ( = 2840) agreed to participate in the study (78% agreed to use the web version and 22% the mailed questionnaire), and 49% of web surveys and 46% of mailed surveys were completed. The final sample included 1331 respondents. The benefits of this approach include the ability to assess sexual minority-specific content in a national probability sample; challenges include high cost and low base rates for Asian and American Indian or Alaska Native individuals in the United States.