The most common way to say "I'm hungry" in Spanish is "Tengo hambre" , which literally means "I have hunger." This is the standard and widely used expression for expressing hunger. There are also other ways to say it with varying intensity or formality:

• "Me muero de hambre" means "I'm starving" (more dramatic).
• "Estoy hambriento" means "I'm famished" (a bit more formal).
• "Quiero comer algo" means "I want to eat something" (casual).
• "Me rugen las tripas" means "My stomach is growling" (informal and humorous).

But for general use, "Tengo hambre" is the most straightforward and commonly used phrase.