diff --git a/math_explorer_gui/src/tabs/clinical_trials/mod.rs b/math_explorer_gui/src/tabs/clinical_trials/mod.rs
index c6c52b90..022df4db 100644
--- a/math_explorer_gui/src/tabs/clinical_trials/mod.rs
+++ b/math_explorer_gui/src/tabs/clinical_trials/mod.rs
@@ -1,9 +1,11 @@
 use crate::tabs::ExplorerTab;
 use eframe::egui;
 
+pub mod randomization;
 pub mod sample_size;
 pub mod survival;
 
+use randomization::RandomizationTool;
 use sample_size::SampleSizeCalculatorTool;
 use survival::SurvivalAnalysisTool;
 
@@ -27,6 +29,7 @@ impl Default for ClinicalTrialsTab {
             tools: vec![
                 Box::new(SurvivalAnalysisTool::default()),
                 Box::new(SampleSizeCalculatorTool::default()),
+                Box::new(RandomizationTool::default()),
             ],
             selected_tool_index: 0,
         }
diff --git a/math_explorer_gui/src/tabs/clinical_trials/randomization.rs b/math_explorer_gui/src/tabs/clinical_trials/randomization.rs
new file mode 100644
index 00000000..e606493e
--- /dev/null
+++ b/math_explorer_gui/src/tabs/clinical_trials/randomization.rs
@@ -0,0 +1,151 @@
+use super::ClinicalTrialsTool;
+use eframe::egui;
+use math_explorer::applied::clinical_trials::design::{
+    AllocationStrategy, BlockRandomizer, Group, SimpleRandomizer,
+};
+
+#[derive(Debug, PartialEq, Clone, Copy)]
+enum RandomizationStrategy {
+    Simple,
+    Block,
+}
+
+pub struct RandomizationTool {
+    n_subjects: usize,
+    strategy: RandomizationStrategy,
+    block_size: usize,
+    assignments: Option<Result<Vec<Group>, String>>,
+}
+
+impl Default for RandomizationTool {
+    fn default() -> Self {
+        Self {
+            n_subjects: 20,
+            strategy: RandomizationStrategy::Block,
+            block_size: 4,
+            assignments: None,
+        }
+    }
+}
+
+impl RandomizationTool {
+    fn trigger_randomization(&mut self) {
+        let mut rng = rand::thread_rng();
+
+        let result = match self.strategy {
+            RandomizationStrategy::Simple => {
+                let randomizer = SimpleRandomizer;
+                randomizer
+                    .assign(&mut rng, self.n_subjects)
+                    .map_err(|e| e.to_string())
+            }
+            RandomizationStrategy::Block => match BlockRandomizer::new(self.block_size) {
+                Ok(randomizer) => randomizer
+                    .assign(&mut rng, self.n_subjects)
+                    .map_err(|e| e.to_string()),
+                Err(e) => Err(e.to_string()),
+            },
+        };
+
+        self.assignments = Some(result);
+    }
+}
+
+impl ClinicalTrialsTool for RandomizationTool {
+    fn name(&self) -> &'static str {
+        "Randomization"
+    }
+
+    fn show(&mut self, ctx: &egui::Context) {
+        egui::CentralPanel::default().show(ctx, |ui| {
+            ui.heading("Randomization Tool");
+            ui.label("Interactive subject allocation for clinical trials.");
+            ui.add_space(10.0);
+
+            ui.horizontal(|ui| {
+                ui.label("Strategy:");
+                ui.radio_value(&mut self.strategy, RandomizationStrategy::Simple, "Simple");
+                ui.radio_value(&mut self.strategy, RandomizationStrategy::Block, "Block");
+            });
+
+            ui.add_space(10.0);
+
+            ui.horizontal(|ui| {
+                ui.label("Number of Subjects:");
+                ui.add(egui::Slider::new(&mut self.n_subjects, 1..=1000).text("Subjects"));
+            });
+
+            if self.strategy == RandomizationStrategy::Block {
+                ui.horizontal(|ui| {
+                    ui.label("Block Size:");
+                    ui.add(
+                        egui::Slider::new(&mut self.block_size, 2..=20)
+                            .step_by(2.0)
+                            .text("Size"),
+                    );
+                });
+            }
+
+            ui.add_space(10.0);
+
+            if ui.button("Randomize").clicked() {
+                self.trigger_randomization();
+            }
+
+            ui.add_space(20.0);
+            ui.separator();
+            ui.add_space(10.0);
+
+            if let Some(ref result) = self.assignments {
+                match result {
+                    Ok(assignments) => {
+                        let treatment_count = assignments
+                            .iter()
+                            .filter(|&&g| g == Group::Treatment)
+                            .count();
+                        let control_count = assignments.len() - treatment_count;
+
+                        ui.horizontal(|ui| {
+                            ui.label(
+                                egui::RichText::new(format!("Treatment: {}", treatment_count))
+                                    .color(egui::Color32::GREEN),
+                            );
+                            ui.label(
+                                egui::RichText::new(format!("Control: {}", control_count))
+                                    .color(egui::Color32::BLUE),
+                            );
+                        });
+
+                        ui.add_space(10.0);
+
+                        egui::ScrollArea::vertical().show(ui, |ui| {
+                            egui::Grid::new("assignments_grid")
+                                .striped(true)
+                                .show(ui, |ui| {
+                                    ui.label(egui::RichText::new("Subject ID").strong());
+                                    ui.label(egui::RichText::new("Group").strong());
+                                    ui.end_row();
+
+                                    for (i, group) in assignments.iter().enumerate() {
+                                        ui.label(format!("Subject {}", i + 1));
+                                        match group {
+                                            Group::Treatment => {
+                                                ui.colored_label(egui::Color32::GREEN, "Treatment")
+                                            }
+                                            Group::Control => {
+                                                ui.colored_label(egui::Color32::BLUE, "Control")
+                                            }
+                                        };
+                                        ui.end_row();
+                                    }
+                                });
+                        });
+                    }
+                    Err(e) => {
+                        ui.colored_label(egui::Color32::RED, format!("Error: {}", e));
+                    }
+                }
+            }
+        });
+    }
+}
diff --git a/todo_gui.md b/todo_gui.md
index 4a0fff5a..66817543 100644
--- a/todo_gui.md
+++ b/todo_gui.md
@@ -114,7 +114,7 @@ This document outlines the roadmap for integrating the various modules of the `m
 *   **Features:**
     *   [x] **Survival Curves:** Kaplan-Meier plot generator.
     *   [x] **Sample Size Calculator:** Form inputs for $\alpha$, $\beta$, and effect size.
-    *   [ ] **Randomization:** Interactive subject allocation tool.
+    *   [x] **Randomization:** Interactive subject allocation tool.
 
 ### 4.3 Favoritism (Satirical)
 *   **Module:** `applied::favoritism`