Timing of the first zygotic cleavage is related to the developmental potential of mammalian embryos. This phenomenon in porcine parthenogenetically activated (PA) and somatic cell nuclear transfer (SCNT) embryos was documented. In vitro matured pig oocytes were either activated parthenogenetically or microinjected with a somatic cell, followed by electro-fusion. At 24 h post activation(hpa), PA and SCNT embryos were assessed visually, and cleaved embryos were moved into new culture wells. This process was repeated at 36 hpa or 48 hpa. Embryos in different groups were allowed to develop for 6 days in culture. The relationship between embryo developmental competence and the first zygotic cleavage at different timing (early-cleaving, 20～24 h; mid-cleaving, 25～36 h; late-cleaving, 37～48 h and unselected controls, 20～48 h) was evaluated by the proportions of cleaved embryos developed to blastocysts and expanded blastocysts (EB), and blastocyst total cell number. For PA embryos, the proportion of early-cleaving embryos that developed to blastocysts was significantly higher than that of mid-cleaving, late-cleaving and controls (P < 0.05; 54.0% vs. 19.6%, 5.4% and 18.7%, respectively); a similar pattern was noted for the formation of EB. For SCNT embryos, the proportion of early-cleaving embryos developing to blastocysts was not significantly higher than that of mid-cleaving embryos (32.2% vs. 23.5%), but the late-cleaving embryos had poor developmental competence to blastocysts (6.3%). Early-cleaving SCNT embryos showed a significant higher competence developing to expanded blastocysts than the mid-, late-cleaving and unselected control embryos (P < 0.05; 18.9% vs. 5.9%, 3.1%, 7.4%, respectively). Total cell number in the blastocysts declined across the three cleavage-timed groups. Developmental potential of SCNT cloned embryos was assessed in vivo by transferring early-cleaving (< 24 h) and unselected (time of cleavage up to 48 h not determined) embryos into recipient gilts. Litter size and cloning efficiency (piglets born/transferred embryos) in recipients of early-cleaving embryos were significantly higher than those in recipients of unselected embryos (4.7 vs. 2.1 piglets; 3.9% vs. 0.9%). The data demonstrate that the developmental potential of early-cleaving SCNT embryos is higher than that of later-cleaving embryos, thus suggesting that timing of the first zygotic cleavage can be utilized as a useful parameter for indicating developmental potential of porcine cloned embryos.