Several dielectric AS well as conducting pipes buried in the lossy half ground are reconstricted from the,scattered fields measured along the air-earn: interface. The iterative inversion method using the hybrid optimization algorithm combining the genetic and Levenberg-Marquardt algorithms is used in finding the positions, sizes, and medium parameters, such as the permittivities and conductivities, of the buried pipe cylinders, as well as those of the background lossy half ground. Ill posedness of the inversion caused by the errors in the measured scattered fields is regularized by filtering out the evanescent modes of the scattered fields. (C) 2001 John Wiley & Sons, Inc.