Structure - activity relationship studies on oxime phosphates against Musca domestica L., Blatta orientalis L., Leptinotarsa decemlineata Say, Sithophilus granarius L., Acyrthosiphon pisum Harris, Tetranychus urticae Koch, were discussed. The compounds studied revealed very slight insecticidal activity in respect to the known and applied zoocides. Some regularity between structure and activity, mainly in comparison with the corresponding enolphosphates, was observed. The highest activity of the compounds with ethoxy groups at the phosphorus atom was shown and the poorest activity was observed for the compounds containing n-propyl groups at this atom. In contrast to enolphosphates the oxime phosphates with methoxy groups at phosphorus atom exhibit particularly poor activity.