Organ transplants rely on donations from both living and deceased donors, yet severe organ shortages persist worldwide. To address this challenge, various policy initiatives have been introduced to enhance both channels of organ supply. This study examines priority-based incentives in organ allocation, specifically policies that grant priority to living donors and individuals who register as deceased donors. We analyze the interaction between these incentives and identify both substitution and complementary effects between living and deceased donation. Our findings suggest that prioritizing registered deceased donors can encourage living donation, provided that living donors receive sufficiently high priority in the allocation process. These insights offer valuable guidance for designing effective policies to increase organ supply.