Benthic diatoms are the main food source for abalone postlarvae and juveniles. To feed abalone postlarvae, seawater is enriched with nutrients to increase natural microalgae populations. Another common method is to feed abalone with a monospecific culture of benthic diatoms. The objective of this work was to evaluate the growth of red abalone postlarvae (Haliotis rufescens) (2.85 ± 0.89 mm shell length; 3.93 ± 2.95 mg weight), fed with Navicula incerta, Amphiprora paludosa var. hyalina and a mixture of both species (1:1 dry weight). Cultures of benthic diatoms were maintained monospecific or mixed in 18-L plastic buckets with f/2 medium. Monospecific and mixed cultures were used to feed abalone postlarvae. The highest protein content (44.87 ±g 10⁶ cells⁻¹) was obtained for the monospecific culture of N. incerta. The highest growth rate (89.71 & plusmn;m d⁻¹) was found in the abalone postlarvae fed with N. incerta. No significant differences (P > 0.05) were found in the growth rate of abalone postlarvae fed with A. paludosa var. hyalina (52.94 μm d⁻¹) or with the mixed culture (53.22 μm d⁻¹). Postlarvae fed with the mixed culture had greater preference for A. paludosa var. hyalina than N. incerta and the lower nutritional value of A. paludosa var. hyalina explained the low growth rate for postlarvae.