Accidental cytogenetic dosimetry is a fundamental tool in radiation emergency preparedness, enabling rapid and reliable assessment of ionizing radiation exposure through the detection of chromosomal aberrations in peripheral blood lymphocytes. In the aftermath of nuclear accidents, radiological attacks, or other radiation-related emergencies, cytogenetic assays—particularly the dicentric chromosome assay—are essential for identifying exposed individuals, even in the absence of clinical symptoms, and guiding timely medical interventions. Recent advancements have underscored the value of molecular biodosimetry as a complementary approach, offering greater sensitivity and mechanistic insight through the detection of DNA double-strand breaks (e.g., γ-H2AX foci), gene expression changes via quantitative real-time polymerase chain reaction (QRT-PCR), microRNA profiling, and genome-sequencing analyses. Together, cytogenetic and molecular techniques enhance dose estimation accuracy, support triage, and inform treatment strategies such as cytokine therapy for acute radiation syndrome. Beyond acute response, these tools play a critical role in the long-term monitoring of public-at-large exposed to radiation, aiding in the detection of delayed effects like cancer and heritable mutations. Integration of these methodologies into preparedness frameworks strengthens public health resilience, improves risk modelling, and supports effective policymaking in the context of radiological emergencies.