Background: Family health history is a strong risk factor for many chronic diseases. Ethnic minorities have been found to have a low awareness of their family health history (FHH), which may pose a contributing factor to health disparities. Purpose: The purpose of this mixed-methods social network analysis study was to identify structural and contextual patterns in African American adults’ FHH knowledge based on interpersonal communication exchanges with their family members. Methods: African American adults completed individually administered family network interviews. Participants’ 3-generation family pedigree served as a visual aid to guide their interview. Our primary outcome of interest for this analysis was whether a family member was reported as someone who talks to the participant about their own (i.e., the family member’s) health, which we refer to as a “personal health informant.” To contextualize quantitative findings, participants were asked to describe how they learned about the health history of the relatives they identified during their interview. Results: Participants (n=37) reported an average family network size of 29.4 relatives (SD = 15.5; Range = 10-67). Each participant, on average, named 17% of their familial network as personal health informants. Multivariate regression results showed that participants were more likely to name an alter as a personal health informant if the alter was female (OR = 2.14, p = 0.0519), from the maternal side of the participant’s family (OR = 1.12, p = 0.0006), had one or more chronic health conditions (OR = 2.41, p = 0.0041), was someone who has discussions with the participant about the participant’s health (OR = 16.28, p < 0.0001), was a source of family health information (OR = 3.46, p = 0.0072), and was someone whose health the participant helps to monitor or track (OR = 5.93, p = 0.0002). Complementary qualitative findings indicate that FHH knowledge is facilitated by open, direct communication among relatives. Personal health informants were described as disclosing information for the purposes of informing others for preventive purposes and for gaining social support. Participants also learned about FHH via other methods, including direct observation, during caretaking, and following a relative’s death. Conclusions: Communication and disclosure practices is an important determinant of African Americans’ FHH knowledge. More culturally and contextually meaningful public health efforts are needed to promote family health history sharing, especially regarding paternal family health history, siblings, and extended relatives.