The boundary effect in electrophoresis can play an important role in applications of practical significance; typical example includes the electrophoresis in a narrow space and that of a concentrated dispersion. This effect is investigated by analyzing the electrophoresis of a spheroid along the axis of an infinite non-conducting cylinder in this study for the case of low surface potential. In particular, the effects of particle aspect ratio, the ratio (linear size of particle/radius of pore), double layer thickness, and the charged conditions on particle surface on the electrophoretic behavior of a particle are discussed. Several interesting results are observed. For example, if the volume of a particle is fixed, its electrophoretic mobility has a local maximum as its aspect ratio varies. Also, if wall effect is important, the relative magnitudes of the electrophoretic mobility of a particle follow the order prolate < sphere < oblate, and the reverse is true if it is unimportant. (C) 2003 Elsevier Ltd. All rights reserved.