Molecular orientation, polarization revel sal, and second-order optical nonlinearity have been studied for the uniaxially drawn aliphatic polyurea films. Aliphatic polyurea (PU7) was synthesized from 1,7-diaminoheptane and urea via a condensation reaction. Melt-pressed films were uniaxially drawn by ratios of 1.4, 1.8, 2.0, 2.5, and 2.8. Clear polarization reversal can be measured when the samples are subjected to the sinusoidal electric field at room temperature and at 60 degrees C which is above the glass transition temperature. Remanent polarization is larger for the sample poled at 60 degrees C than for the sample poled at room temperature. Average molecular angles, <(Phi)over bar>(X), <(Phi)over bar>(Y), and <(Phi)over bar>(Z), in three laboratory frames are evaluated from the refractive indices. <(Phi)over bar>(X) decreases and <(Phi)over bar>(Y), and <(Phi)over bar>(Z) increase with increasing draw ratio. Dependence of second-order harmonic (SH) intensity on incidence angle, i.e., the Maker fringe pattern, could be fitted using two independent tensor components, d(33) and d(31), for undrawn and poled film and three independent tensor components, d(33), d(32), and d(31) for the poled films drawn to a ratio of 1.4 and five independent tensor components, d(33), d(32), d(31), d(15), and d(24), for the poled films drawn to higher ratios of 2.0 and 2.5. For films drawn to the higher ratios of 2.0 and 2.5, Kleinman symmetry was not satisfied: d(31) not equal d(15) and d(32) not equal d(24). Increase of the draw ratio gave rise to the large increase of the tensor components d(33) and d(31), the moderate increase of d(24), and the gradual decrease of d(15) and d(32). The large linear dependence of electrooptic response on electric field is ascribed to the linear electrooptic (Pockels) effect as well as the piezoelectric response.