Background: Uptake of genetic evaluation (GE) remains limited in cancer pts. MGPT is recommended for GE of women with ovarian cancer (OC), but many will never be tested. For pts w/incident colorectal (CRC) and endometrial cancer (EC), universal mismatch repair screening (uMMR) for Lynch syndrome (LS) precedes GE and is also standard of care, but the limited scope of uMMR screening may obscure actionable mutations in non-LS genes, which are more prevalent than LS. We hypothesized that the opportunity to receive MGPT as part of GE would be favorably received by pts having cancer surgery, when relevance is highest. Additionally, to explore variation in timing/approach, we examined completion of a modified GE approach beginning w/MGPT immediately post-op (i-MGPT) vs completion of GE/MGPT when offered via a usual care (UC) pathway (MD- or self-referral). Methods: Women (F)/men (M) w/CRC (n = 20), women w/EC (n = 28) or ovarian cancer/OC (n = 6) were recruited 1-3 days pre/postop (6/2017-1/2018). Interested pts consented and were randomized to i-MGPT vs UC. Those on i-MGPT arm watched a brief pre-testing video about MGPT w/standard genetic counseling available at request. Results were phoned to i-MGPT pts; in-person counseling was encouraged for pathogenic (PV) and uncertain variants. Feasibility was measured by study consent rate (goal > 50%). Results: 56/110 (50.9%) eligible pts consented. Most (89%) reported family history (FHx) of cancer. All pts on i-MGPT arm completed GE: 11% (3/27) had actionable PVs—a BRCA2 PV in a 60F w/EC and FHx pancreas cancer; a BRIP1 PV in a 70F w/OC and FHx breast cancer; a MUTYH PV in a 52M w/CRC. On UC arm, only 40.7% (11/27) have completed GE—PVs in MSH6 (70M w/CRC) and BRCA1 (44F w/OC) were found. Another 29.6% (8/27) on the UC arm with strong cancer risks have not sought GC, including 3 pts with cancer < 50 yrs, a 54F w/OC, and a 70F w/IHC+ CRC and a strong FHx cancer. Conclusions: Perioperative I-MGPT lead to 100% completion of GE while uptake of GE on the UC arm was lower (40.7%). Of the 5 PVs discovered by MGPT, 4 were in non-LS genes. Peri-op MGPT to evaluate hereditary cancer risk is feasible in CRC, EC, and OC pts.