  We present a new void search algorithm for automated detection of voids in
three-dimensional redshift surveys. Based on a model in which the main features
of the LSS of the Universe are voids and walls, we classify the galaxies into
wall galaxies and field galaxies and we define voids as continuous volumes that
are devoid of any wall galaxies. Field galaxies are allowed within the voids.
The algorithm makes no assumptions regarding the shapes of the voids and the
only constraint that is imposed is that the voids are always thicker than a
preset limit, thus eliminating connections between adjacent voids through smal
breaches in the walls. By appropriate scaling of the parameters with the
selection function this algorithm can be used to analyze flux-limited surveys.
We test the algorithm on Voronoi tessellations and apply it to the SSRS2
redshift survey to derive the spectrum of void sizes and other void properties.
We find that the average diameter of a void is $37\pm 8 \h$ Mpc. We suggest the
usage of this fully automated algorithm to derive a quantitative description of
the voids, as another tool in describing the large scale structure of the
Universe and for comparison with numerical simulations.
