Cook the rotini pasta according to package instructions until al dente. Drain and rinse under cold water to cool.

In a large mixing bowl, combine the cooled pasta, cherry tomatoes, cucumber, bell pepper, red onion, black olives, and mozzarella balls.

In a small bowl, whisk together the Italian dressing, dried oregano, salt, and pepper.

Pour the dressing over the pasta salad and toss gently to combine all ingredients evenly.

Cover the bowl with plastic wrap and refrigerate for at least 30 minutes to allow the flavors to meld.

Before serving, give the salad a good stir and adjust seasoning if necessary.