The dynamical influence of Jupiter-sized planets still embedded in protoste
llar disks is studied by means of numerical simulations. The three-dimensio
nal structure of the disk is fully taken into account. Assuming a disk mass
of 3.5 x 10(-3) M. within 2 and 13 AU, typical values for the vertical thi
ckness H/r = 0.05 and viscosity of the disk alpha approximate to 4 x 10(-3)
, we find for the mass accretion rate onto the planet a value of 6 x 10(-5)
M-J yr(-1) and for the migration timescale a value of 10(5) yr. These resu
lts are in excellent lent agreement with previously obtained results from t
wo-dimensional calculations of infinitesimally thin disks. We argue that th
is agreement is to be expected if the vertical height of the disk is simila
r or smaller than the size of the Roche lobe of the embedded planet. Three-
dimensional models having a lower planetary mass or different H/r values di
splay small deviations from two-dimensional results.