Porous Ti implants with various porosities were first fabricated by environmental-electro-discharging-sintering (EEDS) of atomized spherical Ti powders. Powders in two size range (50-100 and 200-250 mu m) were settled by vibration into a quarts tube and subjected to a high voltage and high density current pulse. A single pulse of 0.75-2.0 kJ/0.7 g-powder, using 150, 300 and 450 mu F capacitors, was applied to produce fully porous and porous-surfaced Ti implant compacts. The solid core was automatically formed in the center of the compact after discharge and porous layer consisted of particles connected in three dimensions by necks. The solid core and neck sizes increased with an increase in input energy and capacitance. On the other hand, pore volume decreased with increased capacitance and input energy due to the formation of a solid core. Capacitance and input energy are the only controllable discharge parameters even though the heat generated during a discharge is the unique parameter that determines the porosity of compact. It was shown that EEDS of spherical Ti powders can efficiently produce fully porous and porous-surfaced Ti implants with various porosities in short times (<400 mu s) by manipulating the discharging conditions such as input energy and capacitance including powder size. (c) 2005 Elsevier B.V. All rights reserved.