Cymbopogon citratus (DC.) Stapf (Gramineae) is the scientific name of a plant known as lemongrass. it is characterized by the high concentrations of citral. This work aimed to analyze the influence of short path distillation process variables (evaporator temperature (EVT), volumetric feed flow rate (Q) and interactions between them), on the concentration of citral in the distillate stream of the process. Factorial design experiments were carried out, starting with a 2(2) design trials at experimental range from 60 to 80 degrees C for EVT and from 1.5 to 6.0 mL/min for Q followed by 2(2) with central point design trials at experimental range from 60 to 120 degrees C for EVT and between 1.5 and 4.5 mL/min for Q. The concentration of citral in the distillate (CCD) was analyzed by gas chromatography-mass spectrometry (GC-MS). The effect of each variable studied on the dependent variable (CCD), is indicated by influence of EVT and Q on CCD. The increase of EVT increases CCD to 2.048 x 10(3) mg citral/g sample, when compared with the initial sample of essential oil, which presented a CCD of 9.908 x 10(2) mg citral/g sample. The linear model, statistically significant, describes the dependence of the variable CCD with the variables of the process inside the experimental range. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V All rights reserved.