Bring a large pot of salted water to a boil and add the pasta. Cook until al dente, according to package directions. Drain the pasta in a colander and rinse well with cold water; drain again and transfer to a large serving bowl.
Add the pesto and stir until the pasta is well coated. Stir in the tomatoes, fresh mozzarella, and basil. Season with salt and pepper, to taste. Serve.