The efficiency of biological dephosphatation under conditions of the presence of aromatic hydrocarbons (BTX) in the concentration of 1.0 to 5.3 mg/L has been investigated. As the research material synthetic wastewater, municipal wastewater and the wastewater enriched by supernatant sludge were used. Phosphorus removal efficiency in wastewater treatment process with BTX ranged from 36.4 to 86.3% while, in case of control samples from 22.5 to 83.8%. The estimated average values of dephosphatation efficiency amounted to 72.0% and 67.4% for wastewater treatment with BTX and wastewater treatment without hydrocarbons respectively. The analysis of phosphorus removal efficiency shows that for the lower values of phosphorus concentration in raw wastewater the higher efficiency of phosphorus removal in the samples with BTX were achieved.