To ascertain whether a novel expanded social network recruitment to HIV testing (E-SNRHT) intervention recruits men and individuals with previously undiagnosed HIV at higher rates than risk network recruitment. Initial ‘‘seed’’ participants were prospectively randomly assigned to the E-SNRHT intervention or to risk network recruitment. Their network members were included in the study arm of their recruiter. Three Department of Health clinics and two drug treatment centers (DTCs) in the Msunduzi municipality of KwaZulu-Natal, South Africa. Clinics and DTCs referred 110 newly HIV-diagnosed adult ‘‘seeds’’ to the study from June 2022 to February 2023. E-SNRHT seeds were asked to recruit network members as described below; risk network recruitment arm seeds were asked to recruit recent sex and/or injection partners. Presenting a recruitment coupon (from clinic/DTC staff or another participant) was required for eligibility. E-SNRHT seeds were shown educational material about HIV transmission risks and then asked to recruit anyone they know (e.g., friends, family) whom they thought could benefit from HIV testing. Rates of recruiting men to HIV testing and locating individuals with previously undiagnosed HIV. E-SNRHT recruited significantly higher proportions of men to HIV testing (70.3 vs. 40.4%; x2 ¼16.33; P<0.0005) and located significantly more previously undiagnosed cases of HIV per seed than risk network recruitment (rate ratio ¼9.40; P<0.0001). E-SNRHT also recruited significantly higher proportions of women with previously undiagnosed HIV (29.0 vs. 10.7%; x2 ¼3.87; P ¼0.049). E-SNRHT is an important strategy to expand the reach of HIV testing among men and undiagnosed cases of HIV in KwaZulu-Natal.