Objective The currently observed cloning efficiency is low and can be calculated using different methods.Therefore,a reasonable evaluation method for calculating the cloning efficiency in pigs is important for promoting the application of gene-modified miniature pigs in biomedical fields.Methods In this study,we proposed a method for the scientific evaluation of cloning efficiency in pigs based on the production of cloned Diannan miniature pigs.Results Of 9 recipient gilts that were transferred with cloned embryos,8 (88.9%) gilts became pregnant,and 7 (87.5%) of these delivered 37 piglets,22(59.5%) of which were alive and 17 survived to adulthood (over 1 year of age).Among the 15 stillborn piglets,11 piglets experienced intrapartum death due to dystocia,and the other 4 died due to blastocolysis at the late stage of pregnancy.The greatest number of littermates was 11 piglets.The 3 piglets delivered by Caesarean section were alive and healthy.The procedure used for cloning pigs is a costly process in terms of both time and money;specifically,it requires 677.7-1265.4 min and $715.8-764.5 to transfer 50-400 cloned embryosto a recipient.The cloning efficiency defined as the total number of cloned piglets (including dead and mummy piglets) divided by the total number of transferred embryos was 0.93%,whereas the cloning efficiency obtained based on the total number of live piglets divided by the total number of recipients was 2.44 piglets.The value is higher than those previously obtained using 19 different types of donor cells.Conclusion These findings suggest that donor cells derived from Diannan miniature pigs are a valuable cell source for somatic cell nuclear transfer and the definition of cloning efficiency in pigs as “the total number of live cloned piglets divided by the total number of transferred recipient gilts” may be a reasonable scientific strategy.