diff --git a/src/inputValidation/inputValidation.test.ts b/src/inputValidation/inputValidation.test.ts
index b95dad7..531fcae 100644
--- a/src/inputValidation/inputValidation.test.ts
+++ b/src/inputValidation/inputValidation.test.ts
@@ -3,7 +3,8 @@ import { validateCrs,
     validatePisCode,
     validateReasonCode,
     validateTiploc,
-    validateUuid } from "./inputValidation";
+    validateUuid,
+    validateHeadcode } from "./inputValidation";
 import { ValidationError } from "../errors";
 
 describe("PIS Validation Tests", () => {
@@ -108,3 +109,35 @@ describe("Reason Code Validation Tests", () => {
         expect(() => validateReasonCode({})).toThrow(ValidationError);
     })
 })
+
+describe("Headcode Validation Tests", () => {
+    test("Headcodes of the valid format should return true", () => {
+        expect(validateHeadcode("1A23")).toBe(true);
+        expect(validateHeadcode("5t09")).toBe(true);
+        expect(validateHeadcode("0z70")).toBe(true);
+        expect(validateHeadcode("4A10")).toBe(true);
+        expect(validateHeadcode("0m00")).toBe(true);
+        expect(validateHeadcode("9I94")).toBe(true);
+        expect(validateHeadcode("5u41")).toBe(true);
+        expect(validateHeadcode("5U34")).toBe(true);
+        expect(validateHeadcode("1F34")).toBe(true);
+    })
+
+    test("Headcodes of an invalid format should throw ValidationError", () => {
+        expect(() => validateHeadcode("A212")).toThrow(ValidationError);
+        expect(() => validateHeadcode("a433")).toThrow(ValidationError);
+        expect(() => validateHeadcode(" 1F43 ")).toThrow(ValidationError);
+        expect(() => validateHeadcode("f43a")).toThrow(ValidationError);
+        expect(() => validateHeadcode("&ate")).toThrow(ValidationError);
+        expect(() => validateHeadcode("")).toThrow(ValidationError);
+    })
+
+    test("Headcode inputs that are not strings should throw ValidationError", () => {
+        expect(() => validateHeadcode(4322)).toThrow(ValidationError);
+        expect(() => validateHeadcode([])).toThrow(ValidationError);
+        expect(() => validateHeadcode({})).toThrow(ValidationError);
+        expect(() => validateHeadcode(undefined)).toThrow(ValidationError);
+        expect(() => validateHeadcode(null)).toThrow(ValidationError);
+        expect(() => validateHeadcode(true)).toThrow(ValidationError);
+    })
+})
diff --git a/src/inputValidation/inputValidation.ts b/src/inputValidation/inputValidation.ts
index 2bb217f..2626503 100644
--- a/src/inputValidation/inputValidation.ts
+++ b/src/inputValidation/inputValidation.ts
@@ -67,4 +67,15 @@ export function validateReasonCode(code: unknown): boolean {
 
     // If it's neither a number nor a string, throw an error
     throw new ValidationError("Invalid input: Reason code must be a number or a string of three digits.");
+}
+
+export function validateHeadcode(headcode: unknown): boolean {
+    if (typeof headcode !== "string") {
+        throw new ValidationError("Invalid input: Headcode must be a string");
+    }
+
+    if (!/^\d[A-Za-z]\d{2}$/.test(headcode)) {
+        throw new ValidationError("Invalid input: Headcode must be in the format dLdd where d=digit and L=letter");
+    }
+    return true;
 }
\ No newline at end of file