Studies on somatic embryogenesis and organogenesis of peanut (Arachis hypogaea L.) derived from mature zygotic embryo-derived leaflets of 10 cultivars and two breeding lines representing both runner and Virginia market types were conducted using tissue culture procedures originally optimized for the Spanish market type, J.L. 24. The somatic embryogenesis protocol used was a multi-step process which included embryogenic mass induction, embryo development, germination, and conversion. The percentage of embryogenic mass induction, embryo development, and conversion was genotype-dependent. However, the number of embryos produced per explant and germination to plantlets was genotype-independent. SunOleic® 95R consistently ranked highest for its response during all stages of embryo development, and runner market types were generally more responsive than Virginia market types. The percentage of shoot induction and the number of shoot buds per explant during organogenesis were genotype-dependent, and runner market types were more responsive for organogenesis than Virginia market types. Genotypes with a high embryogenic response also were highly responsive for organogenesis.