Isothermal compression of the Ti600 alloy at the hydrogen contents of 0.16 wt%, 0.31 wt%, 0.45 wt%, 0.65 wt% and natural hydrogen was conducted at the deformation temperatures ranging from 720 degrees C to 1000 degrees C with an interval of 40 degrees C, the strain rates of 0.001 s(-1), 0.01 s(-1), 0.1 s(-1), 1.0 s(-1) and 10.0 s(-1) and a height reduction of 50% on a Gleeble-1500D thermo-mechanical simulator. The effect of hydrogen content on the flow stress of Ti600 alloy was analyzed. A fuzzy neural network (FNN) was applied to acquire the correlation model between the hydrogen content, deformation temperature, strain rate, strain and the flow stress in the isothermal compression of Ti600 alloy. The present model could be used to predict the flow stress of Ti600 alloy at different hydrogen contents. The average difference of the predicted using the FNN model from the experimental flow stress in the isothermal compression of Ti600 alloy is 8.2%. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.