We tested whether differences in composition and nutrients of diet explained higher density of Peromyscus aztecus in mature cloud forest and higher density of Reithrodontomys fulvescens in disturbed cloud forest. P. aztecus ate dicot leaves, stems, fruit, and seeds in mature cloud forest and dicot leaves, stems, and seeds, and monocot seeds and insects during the dry-hot season in disturbed cloud forest. R. fulvescens ate dicot leaves, stems, fruit, and seeds in mature cloud forest but monocots and insects during the hot season; dicot leaves, stems, and seeds were eaten in disturbed cloud forest. The diet of P. aztecus contained more protein and soluble carbohydrates in disturbed cloud forest where rodent density was lower; the diet of R. fulvescens contained more protein, lipid, soluble carbohydrate, Na, Mg, and P in mature cloud forest where density was lower. Nutrient differences resulted from R. fulvescens eating more monocots and dicot fruit, P. aztecus eating more monocot seeds and less dicot fruit, and both species eating more insects. Differences in composition or nutrient content of diet did not explain between-habitat differences in demography because nutrients in diet were higher in habitat of lower rodent abundance, suggesting other factors must be considered.