In this work, pyrolysis of sewage sludge in a fluidized bed was studied experimentally in order to obtain a liquid product able to be used in energetic applications. The influence of operational conditions on the product distribution was studied. The operational variables were as follows: temperature (450-650 degrees C), nitrogen flow rate (3.5-5.5 L(NTP) min(-1)), and solid feed rate (3.0-6.0 g min(-1)). Their influence was considered on the yields to the three pyrolysis products: solid, liquid, and gas. The liquid yield was mainly influenced by the bed temperature but also by the nitrogen flow rate and the solid feed rate. The bed temperature and the nitrogen flow rate showed a quadratic effect, and the maximum liquid yield was achieved at around 540 degrees C and around 4.5 L(NTP) min(-1) of nitrogen. The solid feed rate just affected on the liquid yield at the lower temperatures studied, and the maximum liquid yield was obtained at the lowest solid feed rates. The design of experiments (DOE) statistical tool was used in the preparation of the work.