diff --git a/src/index.spec.ts b/src/index.spec.ts
index 4c9b026f..2e69c3a7 100644
--- a/src/index.spec.ts
+++ b/src/index.spec.ts
@@ -182,6 +182,17 @@ describe('Package', () => {
 
 			assert.deepStrictEqual(actual, expected);
 		});
+
+		it('should clean up patterns', () => {
+			const expected = [
+				// Clean up duplicated slashes
+				tests.task.builder().base('fixtures').positive('fixtures/*').build()
+			];
+
+			const actual = fg.generateTasks(['fixtures//*']);
+
+			assert.deepStrictEqual(actual, expected);
+		});
 	});
 
 	describe('.isDynamicPattern', () => {
diff --git a/src/index.ts b/src/index.ts
index b6ef0c2d..9f957bd7 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,4 +1,5 @@
 import * as taskManager from './managers/tasks';
+import * as patternManager from './managers/patterns';
 import ProviderAsync from './providers/async';
 import Provider from './providers/provider';
 import ProviderStream from './providers/stream';
@@ -58,7 +59,7 @@ namespace FastGlob {
 	export function generateTasks(source: PatternInternal | PatternInternal[], options?: OptionsInternal): Task[] {
 		assertPatternsInput(source);
 
-		const patterns = ([] as PatternInternal[]).concat(source);
+		const patterns = patternManager.transform(([] as PatternInternal[]).concat(source));
 		const settings = new Settings(options);
 
 		return taskManager.generate(patterns, settings);
@@ -80,7 +81,7 @@ namespace FastGlob {
 }
 
 function getWorks<T>(source: PatternInternal | PatternInternal[], _Provider: new (settings: Settings) => Provider<T>, options?: OptionsInternal): T[] {
-	const patterns = ([] as PatternInternal[]).concat(source);
+	const patterns = patternManager.transform(([] as PatternInternal[]).concat(source));
 	const settings = new Settings(options);
 
 	const tasks = taskManager.generate(patterns, settings);
diff --git a/src/managers/patterns.spec.ts b/src/managers/patterns.spec.ts
new file mode 100644
index 00000000..bdac5a4e
--- /dev/null
+++ b/src/managers/patterns.spec.ts
@@ -0,0 +1,57 @@
+import * as assert from 'assert';
+
+import * as manager from './patterns';
+
+describe('Managers → Pattern', () => {
+	describe('.transform', () => {
+		it('should do not change patterns', () => {
+			const expected = [
+				'directory/file.md',
+				'files{.txt,/file.md}'
+			];
+
+			const actual = manager.transform([
+				'directory/file.md',
+				'files{.txt,/file.md}'
+			]);
+
+			assert.deepStrictEqual(actual, expected);
+		});
+
+		it('should do not change the device path in patterns with UNC parts', () => {
+			const expected = [
+				'//?/D:/',
+				'//./D:/',
+				'//LOCALHOST/d$/',
+				'//127.0.0.1/d$/',
+				'//./UNC/LOCALHOST/d$/'
+			];
+
+			const actual = manager.transform([
+				'//?//D://',
+				'//.//D:///',
+				'//LOCALHOST//d$//',
+				'//127.0.0.1///d$//',
+				'//./UNC////LOCALHOST///d$//'
+			]);
+
+			assert.deepStrictEqual(actual, expected);
+		});
+
+		it('should remove duplicate slashes in the middle and the of the pattern', () => {
+			const expected = ['a/b', 'b/c', 'c/d/', '//?/D:/'];
+
+			const actual = manager.transform(['a//b', 'b///c', 'c/d///', '//?//D://']);
+
+			assert.deepStrictEqual(actual, expected);
+		});
+
+		it('should form double slashes at the beginning of the pattern', () => {
+			const expected = ['//*', '//?', '//?/D:/'];
+
+			const actual = manager.transform(['///*', '////?', '///?/D:/']);
+
+			assert.deepStrictEqual(actual, expected);
+		});
+	});
+});
diff --git a/src/managers/patterns.ts b/src/managers/patterns.ts
new file mode 100644
index 00000000..5a7a4378
--- /dev/null
+++ b/src/managers/patterns.ts
@@ -0,0 +1,17 @@
+/**
+ * Matches a sequence of two or more consecutive slashes, excluding the first two slashes at the beginning of the string.
+ * The latter is due to the presence of the device path at the beginning of the UNC path.
+ */
+const DOUBLE_SLASH_RE = /(?<!^)\/{2,}/g;
+
+export function transform(patterns: string[]): string[] {
+	return patterns.map((pattern) => removeDuplicatedSlashes(pattern));
+}
+
+/**
+ * This package only works with forward slashes as a path separator.
+ * Because of this, we cannot use the standard `path.normalize` method, because on Windows platform it will use of backslashes.
+ */
+function removeDuplicatedSlashes(pattern: string): string {
+	return pattern.replace(DOUBLE_SLASH_RE, '/');
+}