The aim of this experiment was to determine the efficacy of different inclusion levels of new type phytase (ECP) synthesized by Escherichia coli and expressed in Pichia pastoris yeast (Optiphos) in maize-soyabean meal based diets on egg quality and the laying performance of laying hens aged from 20 to 44 weeks. Two hundred and twenty Lohmann Brown hens were randomly assigned to five treatments with 44 replicates each, and were kept individually in cages. The control diet (C) contained 2.5 g non-phytate phosphorus (NPP) and 35.5 g Ca/kg feed, and the experimental diets contained 1.3 g NPP and 33.0 g Ca/kg feed. The deficient diet (D) was offered without any addition of phytase, while the other treatments involved different levels of this enzyme: 125, 250 and 500 FTU/kg feed (treatments ECP₁₂₅, ECP₂₅₀ and ECP₅₀₀, respectively). Compared with the deficient diet, phytase supplementation significantly affected the performance of hens over the entire experimental period (number of eggs laid, egg mass and FCR), and egg quality parameters: egg yolk colour (significantly in week 24 of the laying period) and shell thickness (significantly in week 12 of the laying period). The results of the present study indicate that the supplementation of diets for laying hens with ECP improved performance parameters. The NPP content of layer diets based on maize meal and soyabean meal can be reduced by 1.2 g/kg provided that the diets are supplemented with ECP at 125-250 FTU per kg diet.