The data presented here are the biochemical parameters of 156 patients with hyperphenylalaninemia. PKU patients, who, in order to maintain optimal serum Phe concentrations, receive dietary treatment consisting of a diet low in natural protein supplemented with special low protein foods and a Phe-free amino acid mixture, vitamins and minerals. The obtained data reflects a high percentage of patients with prealbumin and selenium deficiencies, as well as an increased level of folic acid. This data article is related to the research article entitled, "Vitamin and mineral status in patients with hyperphenylalaninemia", by Crujeiras et al. [1].