Tomatoes should be rinsed thoroughly before preparation. If they are being used to make tomato sauce for spaghetti or other dishes, they should be peeled and seeded. To peel a tomato, drop it into boiling water for one to two minutes. Then remove and dunk briefly in a bowl of ice water. Cut out a small cone around the stem end and slip off the skin. To seed a tomato, cut it in half horizontally and squeeze the seeds out.

Raw fresh tomatoes are most often sliced onto sandwiches or eaten in salads. They can also be cooked with herbs, onions, and garlic to make homemade spaghetti sauce. Raw tomatoes can be diced and added to soups or stews. Halved tomatoes can also be broiled. Place them on a baking sheet, drizzle with olive oil, and broil until the tops are lightly browned, about five minutes. Tomatoes make an attractive dish when stuffed with crabmeat or with sautéed vegetables, such as spinach and mushrooms, and baked.

Unripe, green tomatoes are often dipped in cornmeal and fried.

Canned tomatoes can be added to soups, stews, or bean dishes, or used to make spaghetti sauce. Combined with vegetable broth, they make a good base for many kinds of soups. Canned tomatoes can be puréed with soft tofu and then thinned with milk, soy milk, or broth, flavored with herbs, and heated to make a fast cream of tomato soup. Canned tomato sauce can also be used in curry dishes and to make chili.

Never add canned tomatoes to uncooked beans or grains, since they toughen the skins of these foods, making it difficult to cook them to a tender stage.

Unless they are packed in oil, dried tomatoes (sometimes called sun-dried tomatoes) must first be slightly rehydrated by allowing them to soak in hot water. Dried tomatoes can be chopped and tossed with pasta or vegetable dishes. They can also be puréed with olive oil, toasted pine nuts, and basil to make tomato pesto.