Summary: In the 80s, radiolabeled cells helped understand the pathology of hemato-oncology. In the 90s, pre-clinical trials evaluated radiolabeled immunotherapy with monoclonal antibodies (MoAbs) such as anti-CD20 agents labeled with Iodine-131 (Bexxar®) or Yttrium-90 (Zevalin®). Due to the safe and durable responses of radiolabeled-MoAbs, the FDA approved these agents in the 2000s. Despite radioimmunotherapy's long journey, its application has recently decreased. This review will discuss the historical timeline of radioimmunotherapy, debate on advantages and difficulties, and explore trials. Furthermore, we will examine future directions of radioimmunotherapy in hemato-oncology, considering emerging molecules that may become the next theragnostic trend. Conclusão: Since the 1980s, radiolabeled cells have been instrumental in understanding the pathological dynamics of hemato-oncological diseases. The evolution of this approach traversed the hybridoma technique in the 1990s, leading to numerous pre-clinical trials involving Monoclonal Antibodies (MoAbs). Subsequent clinical trials, predominantly in the 2000s, extensively explored MoAbs, focusing on anti-CD20 agents labeled with either 131I (Bexxar) or 90Y (Zevalin). The FDA approved these therapies in 2002 and 2003, marking significant milestones recognizing their safety and enduring therapeutic responses. Despite this journey, there has been a consistent decline in prescriptions. Various factors contribute to this trend, encompassing availability issues, reimbursement challenges, regulatory complexities, the need for trained personnel, and intricate logistics. Recent pre-clinical and clinical trials have shifted the spotlight onto novel antibodies, peptides, and further applications of known tracers. This renewed exploration may incentivize new suppliers to redirect their attention, potentially heralding the next wave of theragnostic trends in the near future.