The study presents the results of determining of phthalate metabolites in urine of pre-school and primary school children by HPLC/MS. The correlation between growth rate of children and the concentration of phthalate metabolites in their urine was examined. The detected range of phthalate metabolite concentrations (mono-methyl phthalate, mono-butyl phthalate, mono-ethylhexyl phthalate) in urine of children was 0.0004–0.012 mg/dm3.