India's fisheries and aquaculture sector demonstrates robust growth, yet small and marginal fish farmers persist with challenges in input access, risk management and market infrastructure. The Pradhan Mantri Matsya Sampada Yojana (PMMSY) addresses these through integrated interventions spanning production enhancement, post-harvest infrastructure, capacity building, and social protection. This study evaluates PMMSY beneficiaries' techno-economic impacts in Karnataka's Kalyana Karnataka region. Employing purposive sampling across Raichur, Yadgir, and Ballari districts, primary data were collected via pre-tested structured interviews from 240 beneficiaries (120 small-scale [<5 ac] and 120 large-scale [≥5 ha] farmers). Impact was assessed using structed schedule, while economic outcomes were analyzed via Difference-in-Differences (DiD) modeling (R²=0.73). Results revealed significant enhancements in operational landholdings, gross/net incomes, returns per rupee invested and cost reductions across both groups (p<0.01). Household assets, mechanization, organizational participation and social status improved markedly, with a shift toward full-time aquaculture. The DiD model confirmed positive, significant influences of labor, feed, fingerlings, medicines and lime on production (p≤0.05), with large-scale farmers achieving comparatively greater gains, though smallholders also realized substantial benefits. Findings underscore PMMSY's efficacy in fostering inclusive growth, recommending targeted intensification for smallholders to optimize scheme outcomes.