Preparations with repellent effects in the form of lotion and ointment are formulated. The active substance is Deet (N,N-diethyl-toluamide) and the base constitutes of isopropanil and polyethylene glycol 300 and 1500. The physico-chemical examinations (Deet identification, examination of density, refraction index and Deet contents) have been previously performed. By these investigations the Deet structure was conformed, relative density was determined (1,0014) and also the refraction index (1,5211) (BP 80; USA XXI). The nitrogen (N) content in the resulting substance was 6.44%, in lotion 2.27% and in ointment 0.49%, which correspond to the contents of Deet in the formulated preparations. The evolution of biological efficacy was performed on Ixodes ricinus ticks. The preparation has shown protective effects to the presence of ticks over 60 min under field conditions and up to 146 min under laboratory conditions.