Genotypes selection and optimizing mineral nitrogen, phosphorus and potassium fertilization are important factors that influence flax growth, yield and quality. Two field experiments were conducted at the Experimental Research Station in Esmailia, Field Crops Research Institute, Agricultural Research Center, Egypt during the growing seasons of 2012/2013 and 2013/2014 seasons to study the effect of mineral nitrogen, phosphorus and potassium fertilization on yield and quality of some flax genotypes under sandy soils conditions. The experiments were carried out in a split-plot design with three replicates. The main-plots were assigned to flax genotypes (Giza 10, Sakha 2 and strain 22). The sub-plots were allocated to mineral fertilization treatments (fertilizing with mineral N, P, K, NPK and without mineral fertilization). The results indicated that significant differences among the three studied flax genotypes i.e. Giza 10, Sakha 2 and strain 22 were detected in all studied characters, except number of seeds/capsule in both seasons. Fertilizing flax plants with 75 kg N + 23.25 kg P₂O₅ + 24.0 K₂O/fed significantly increased all studied characters and produced the highest values as compared with other studied mineral fertilization treatments in both seasons. Control treatment (without mineral fertilization) gave the lowest values of all studied characters. On the basis of the results obtained, maximum straw and seed yields and its components of flax could be achieved through fertilizing Strain 22 or Sakha 2 genotypes with 75 kg N + 23.25 kg P₂O₅ + 24.0% K₂O/fed. However, maximum fiber flax yield resulted from  fertilizing Giza 10 cultivar with 75 kg N + 23.25 kg P₂O₅ + 24.0 K₂O/fed under sandy soils conditions in Esmailia Governorate.