For the modeling of erythrocyte rouleaux we develop an approximation procedure for the dipole moment in short cylinders, which contains the case of ellipsoidal bodies only as a first approximation, but allows to include corrections for short cylinders, more representative for such particles. In dependence on the number of erythrocytes forming an aggregation, i.e. on different but discrete measures of rouleaux lengths, the dielectrophoretic force is calculated and represented against the frequency of the applied a.c. field. Predictions of frequency regions in the range of 10(7) to 10(8) Hz are made, where the amount and the direction of dielectrophoresis forces is different for different rouleaux sizes.