QUESTION ASKED: How much downstream revenue do cancer genetic counselors (GCs) generate when they identify patients with hereditary breast and ovarian cancer (HBOC) ( BRCA1/BRCA2) and Lynch syndrome (LS) pathogenic variants? SUMMARY ANSWER: Over a 10-year period, the downstream revenue generated from cancer GCs’ identification of patients with HBOC and LS was $32.79 million in US dollars (USD) (mean/year = $3.25 million USD and mean/patient = $77,000 USD). One full-time GC would generate $1.49-$1.86 million USD in revenue per year ($1.26-$1.58 million USD for HBOC-positive patients and $227-$284,000 USD for LS-positive patients per year). WHAT WE DID: Expected reimbursement and work relative value units (wRVUs) were collected from all hospital and ambulatory or outpatient encounters for patients with HBOC or LS identified in the Cancer Genetics clinic. Total revenue was calculated for each patient after they met with a GC; patients were stratified into categories of affected or unaffected status and new or established patients in the hospital system. WHAT WE FOUND: The downstream revenue generated from 425 patients with HBOC or LS mutations totaled $32,798,000 USD and 73,957 work relative value units after their cancer genetics appointments. Patients unaffected with cancer (n = 176) generated $8,453,000 USD, whereas naïve patients (n = 96), defined as those whose first visit to the institution was for a genetic counseling consultation, generated $5,933,000 USD. BIAS, CONFOUNDING FACTOR(S): This study solely focuses on revenue generated from patients with HBOC or LS. However, with the advent of next-generation sequencing panels, many pathogenic variants are being identified in other genes, resulting in enhanced management recommendations. Therefore, the revenue brought in by a GC likely surpasses the data provided here. Additionally, these data focus strictly on downstream revenue generated from patients receiving follow-up care at our institution. Patient adherence to compliance of management recommendations can affect the overall amount of revenue generated. REAL-LIFE IMPLICATIONS: To our knowledge, this is the first study to describe the amount of revenue generated for an institution downstream of the identification of pathogenic variant carriers in cancer susceptibility genes by a GC. These data will aid healthcare systems and oncology practices in determining if there is standalone fiscal value to the downstream effect of genetic counseling services or if services need to be supplemented through other avenues. By identifying clinic demographics and volumes, test uptake rate, and positive pathogenic variant rate, cancer GCs and healthcare systems or oncology practices can determine the expected revenue generated from HBOC and LS pathogenic variant carriers at their own institution to justify positions and growth of their genetic counseling departments ( Fig. 1 ).