Effects of dietary nucleotide supplementation on growth and feed efficiency in rainbow trout (initial weight = 25 g/fish) were conducted in a 70-day growth trial. One control diet and two basal diets (25%, 5% and 0% fish meal, respectively) were formulated using high levels of highly digestible plant protein ingredients to meet all the known nutrient requirements of rainbow trout. Two basal diets were supplemented with four increasing levels (0, 8, 16 and 24 ppm, respectively) of nucleotides using a commercial supplement (Laltide®, Lallemand Inc. Qc, Canada). Nucleotide supplementation levels significantly (p<0.05) affected final body weight and feed efficiency in rainbow trout fed with the 5% fish meal diet. The results of this study suggest that dietary nucleotide supplementation may be beneficial to young rainbow trout fed with low fish meal and high levels of plant protein ingredients. The essentiality of nucleotides to young rainbow trout deserves to be further examined.