diff --git a/String/CheckCamelCase.js b/String/CheckCamelCase.js
new file mode 100644
index 000000000..d15a35663
--- /dev/null
+++ b/String/CheckCamelCase.js
@@ -0,0 +1,20 @@
+// CheckCamelCase method checks the given string is in camelCase or not.
+
+// Problem Source & Explanation: https://en.wikipedia.org/wiki/Camel_case
+
+/**
+ * CheckCamelCase method returns true if the string in camelCase, else return the false.
+ * @param {String} varName the name of the variable to check.
+ * @returns `Boolean` return true if the string is in camelCase, else return false.
+ */
+const CheckCamelCase = (varName) => {
+  // firstly, check that input is a string or not.
+  if (typeof varName !== 'string') {
+    return new TypeError('Argument is not a string.')
+  }
+
+  const pat = /^[a-z][A-Za-z]*$/
+  return pat.test(varName)
+}
+
+module.exports = CheckCamelCase
diff --git a/String/CheckPascalCase.js b/String/CheckPascalCase.js
new file mode 100644
index 000000000..6babce5f0
--- /dev/null
+++ b/String/CheckPascalCase.js
@@ -0,0 +1,20 @@
+// CheckPascalCase method checks the given string is in PascalCase or not.
+
+// Problem Source & Explanation: https://www.theserverside.com/definition/Pascal-case
+
+/**
+ * CheckPascalCase method returns true if the string in PascalCase, else return the false.
+ * @param {String} VarName the name of the variable to check.
+ * @returns `Boolean` return true if the string is in PascalCase, else return false.
+ */
+const CheckPascalCase = (VarName) => {
+  // firstly, check that input is a string or not.
+  if (typeof VarName !== 'string') {
+    return new TypeError('Argument is not a string.')
+  }
+
+  const pat = /^[A-Z][A-Za-z]*$/
+  return pat.test(VarName)
+}
+
+module.exports = CheckPascalCase