The present study was carried out to establish aggregation procedures of bovine inner cell mass (ICM) cells and tetraploid embryos to produce cloned cattle in a different way from nuclear transfer. Bovine two-cell embryos produced by in vitro fertilization were exposed to the electric pulse to fuse 2 blastomeres resulting in tetraploid embryos. Nine (18.8%) of 48 embryos fused by electrofusion developed to blastocyst stage. Three (16.7%) aggregates consisting of two putative tetraploid embryos and one clump of ICM cells developed to blastocyst. And the aggregates which were aggregated with a clump of bovine mammary cells and a clump of ICM cells which were stained with Hoechst also developed to blastocysts. These blastocysts were illuminated by UV, overall or some parts of all ICM of the aggregates treated were observed to luminesce. This raises the possibility that the clumps of the cells can form some parts of ICM of the aggregates. These results indicate that the aggregates of a clump of ICM cells or mammary cells and tetraploid embryos developed to blastocyst stage and that some parts of ICMs of the aggregates were originated from the clump of cells.