Modeling of atmospheres of the brightest stars belonging to the Cyg OB2 association O LGA M A RY E VA , V. G . K L O C H K OVA , E.L. C H E N T S OV Special Astrophysical Observatory RAS; olga.maryeva@gmail.com We present the results of modeling of the spectrum of the brightest stars belonging to the Cyg OB2 association ­ Cyg OB2 #7 (O3If ) and Cyg OB2 #11 (O5Ifc). ... The lines in Cyg OB2 #7 spectrum are divided into three groups which can not be described with a single model. ...