The present invention relates to a Lactuca sativa seed designated 81-64 RZ, which exhibits a combination of traits including resistance to downy mildew (Bremia lactucae) races Bl:1 to Bl:28, Bl:30-Bl:32 and Ca-I to Ca-VIII, resistance to currant-lettuce aphid (Nasonovia ribisnigri) and resistance to corky root (Sphingomonas suberifaciens) race CA1, as well as having non-flabellate leaves. The present invention also relates to a Lactuca sativa plant produced by growing the 81-64 RZ seed. The invention further relates to methods for producing the lettuce cultivar, represented by lettuce variety 81-64 RZ.