Somatic cell nuclear transfer (SCNT) is a useful technique for the production of transgenic pigs that can be used for biomedical research. However, the efficiency of SCNT in pigs is low. In this study, we examined the effect of two postactivation treatments, cytochalasin B (CB) and trichostatin A (TSA), on the in vitro development of porcine SCNT embryos. Treating porcine parthenotes with 7.5 microg/mL CB for 3 h after electrical activation was effective in preventing the extrusion of the second polar body in 65% of the oocytes compared to 17% in the control group. Treating SCNT embryos with CB for 3 h after electrical activation significantly increased the average blastocyst cell number compared to the control group (CB treatment 51, Control 34, p < 0.05). Treatment of porcine SCNT embryos with CB for 3 h and 50 nM TSA for 24 h after electrical activation resulted in a threefold increase in blastocyst rate (CB + TSA 64%, CB 20%, p < 0.05) and an increase in the average blastocyst cell number (CB + TSA 63, CB 46, p < 0.05), compared to CB treatment alone. These results show that treatment with TSA and CB significantly improves the in vitro morphological development and quality of porcine SCNT embryos.